You do have to start in a regio. Hence, the sentence in the last full paragraph on the cneter column on pg. 92, "A mundane destination can only be reached by first traveling to a level of a regio above it...." Ergo, we need to find a regio, preferably a faerie one.
To get to a mundane place, you do have to go to the regio above it first. However...
Arcadian Travel provides an alternate means of exiting a regio, aside from any "normal" exits: hence the Ease Factor for Leave Regio in the table at the bottom of pg. 92. The Ease Factor for a mundane target presumably applies only when using Arcadian Travel in this fashion.
If you can get out of a regio by "normal" means, you don't need to use Arcadian Travel for the last leg of a journey to a mundane location.
You don't have to pass through Arcadia. Despite the name of the Mystery, note the text of the first incomplete) sentence of the middle column of pg. 92, "...can even lead to Arcadia." [emphasis added]
It looks like our key difficulty is that our most likely regio, Viola's lab, has an aura of 5. If she had an arcane connection, it might be doable; I've never thought to tote one around, but all of this raises the question of how she did it during the Chersonesus story.
Re-reading...you're right that I'd missed that you have to go to a regio before reaching the mundane world (I'd not been sure, but then had decided you could go straight from Arcadia. However, as you point out, there's that sentence explicitly saying you have to travel to a mundane location via a regio about it first).
However, I think that then means you have to go mundane world -> regio -> Arcadia -> regio -> mundane world (although as you say, you can do the getting into and out of regiones bits by mundane means rather than Arcadian travel if that's an option, which it will be for Viola's lab) - whilst I agree that going through Arcadia isn't an inherent part of Arcadian travel, I think it's generally required if you want to go long distances (as most regio don't connect to other regiones directly). So you can skip the Arcadia bit if you're just trying to get in or out of a regio, but if you're trying to use it to go long distances (and don't have a convenient (Land) regio network virtue) you need to go via Arcadia.
As far as the Chersonesus story goes - you had the advantage of starting with a regio there, which you don't have now, and we were handwaving, so I didn't check the requirements when you said you'd done the rolls and passed them.
(Explanation B is that Viola only used it to get out of the regio to Chersonesus, and then used LLSM to Wizard Leap back rather than using Arcadian travel).
I think at some point I made a conscious decision for her not to carry around an AC to her lab, so that explains that.
At any rate, I'm 95% sure the mystery is only supposed to require one roll in most instances. While the reasoning that trips to Arcadia would be required for long distances is logical, I don't think it's supported by the RAW at all--especially when you consider that they explicitly note that trods connect regiones, and put the "even" and "can" in front of the mention of Arcadia. From the standpoint of game balance, requiring the trip to Arcadia would make the difficulty prohibitive, especially when compared with other means of long-distance travel, most of which don't require Mysteries at all, let alone a roll that relies on a single Ability rather than a pair of Arts.
Then there's also the amusing omission of any description of what happens on a failed roll.
Has this never come up in the forums? Should we ask?
Of the two, the second seems to be the most useful, particular the reference to RoP: Faerie pp. 24-25 in the second post--the section in question helpfully provides color text that justifies travel of unlimited distances.
It's notable that no one in either thread seems to suggest a need to make multiple rolls. Mind you, even without this, Viola still needs to find a regio. And we need to figure out what happens on a failed roll, because that's a very real possibility. Nonetheless, if we could find a regio with an aura of, say, 3, that would be Craft 2 + 1 for specialization +2 Per + Aura 3 + stress die of 7 or more--not totally out of the realm of the possible. And with an AC, it would be easy to make a return round trip.
Free Expression should arguably apply as well, since it's integral to creating the charm in the first place--and in general creativity is helpful in getting stuff done in the faerie realm (see the section of RoP: Faerie beginning on pg. 27).
Erik Dahl does seem to say that, but I still don't think that's how the rule was actually published; I don't know if an editor intervened, but looking back at the early sentence that refers to travel between "the different levels of regiones", I can see the intent. Mind you, that makes the Mystery much less useful.
OTOH, the "ARCADIAN MYSTERIES" section on pg. 23 of RoP: Faerie in effect makes it possible to boost the roll for getting to Arcadia by using all the modifiers on the previous two pages. Would those bonuses also apply to leaving Arcadia?
And on the third hand...I assume Dominion auras don't go very far into the air. Could we just have Constantine grow to large size and let him fly the barley over the Dominion?
That was actually the source of me thinking that it would be possible to bypass going through a regio to get to Arcadia. I'm inclined to say no, on the basis that the mechanics for leaving Arcadia seem to be quite different from entering it (and it's not mentioned in the box "Leaving by Using Merinita Mysteries" on page 29).
I don't think aura heights are very well defined. In the case of a Dominion aura, though, I'd probably say as high as you can hear church bells is going to have something (give this tends to determine the spread on the ground), which is probably going to be quite a distance.
I thought you were trying to go to Athens' harbour - Eleusis isn't a port, it just overlooks the sea. You can go down to the coast, but you'll have to send someone to find a boat. How big a one are you looking to hire? It's going to be much easier to get something small than something suitable for a significant voyage.
Alright - let's say that with a bit of difficulty (and a fair amount of money), the grogs successfully hire some fishermen with a small boat, that can then liaise with a larger ship.
You're pretty sure they think you're smuggling something. Or possibly a fugitive?
Getting back to the covenant isn't entirely smooth - in particular, you have to engage in some interesting manouvering around Constantinople, and again to avoid taking the grain through the village near the covenant, but finally its surrounding ring of trees is in sight.
Calliope needs to make some tweaks to the song, in light of what you actually got from "Demeter", and then Ipek needs to spend a few seasons spreading it. You then need to enact the finale.
The other thing to be considering is what you're going to do about the barley - much of the original Moon duration has expired by the time you reach the covenant. Are you going to attempt to reproduce it, or somehow maintain the existing spell, or just use it as an unenchanted prop?
Viola's Magic Theory level is a lot higher than mine, but I'm under the impression that extending the duration of a non-Hermetic effect exceeds the bounds of Hermetic magic. As for Viola's knowledge of MT:
Magic Theory 8 + 4 Int + simple die 1 = 13; if that's supposed to be a stress die, the second roll is a 9, making the total a 30.
If Viola knew of an aura where time reliably went more slowly than in the mundane world, parking the barley there might be an option, but the typical case is a faster progress of time.
As Viola noted before, it's at least possible that the Moon duration starts once the brew is mixed. It's also possible that if we fed her the brew now, the snakes would sleep for some extended period of time. Is there enough barley to make more than one brew?
[OOC: It varies by technique - Muto Vim-ing a non-Hermetic effect is explicitly disallowed (and only affects spells whilst they're in the process of being cast anyway), whilst Perdo Vim-ing a non-Hermetic effect is explicitly allowed if the caster has some knowledge of the type of magic (but they don't have to be able to cast it). Intellego is very strongly implied to be possible. Rego and Creo don't say, as far as I can tell (and Creo probably doesn't make much sense), but my inclination would be to allow Rego Vim on a non-Hermetic effect subject to having a good understanding of the effect.
She'd therefore need to:
Cast an Intellego spell high enough to capture the level of the spell, with 3 extra magnitudes for detail (which should be enough to give you the Technique and Form equivalent and a rough idea of what the spell's doing)
Successfully interpret the information using Int + Faerie Lore vs EF 15 (This is fairly high given you're using a fairly general lore rather than something specific to a tradition).
Use the "Sustain or Suppress a Spell cast by another with level less than or equal to half the (level + 5 magnitudes) of the vim spell" guideline (and assume that it's possible to sustain a non-concentration duration spell past its natural duration)
So basically, not easy, but Viola has both LLSM and a reasonable Int + Faerie Lore score, so it's not completely out of the question if she wishes to take the risk of casting high level spells using LLSM every fortnight.]
For the barley to start working only once the brew is mixed, it would have to essentially be a charged item (or something equivalent like extraordinary vis). That doesn't seem very likely, but you'd have to investigate what the magic on the barley actually was to be sure.