For those who didn't see it, Peregrinatores (RPGTrader, DriveThruRPG) is a campaign guide for running a peregrinatore saga in the Rhine Tribunal. It includes material on the Rhine's culture around travelling magi, a guide to the covenants of the Rhine with information on the resources available, and information on founding new covenants and chapter houses. It has a bunch of rules and systems for all of those things, plus a set of solo rules,inspired by Monster of the Week's "Case Closed," to support play as a journalling game.
There are errors in the book. Waddenzee has in fact accepted peregrinatores in the past (Imanitos Mendax studied there), and there will no doubt be others. Please report them here. If I get enough I'll set up an errata file somewhere and eventually adjust the PDF (updating the hardcopy version is more dfficult, at lest for DriveThru). I also need to upload @Lothindil's fabulous CC-BY-SA map to Redcap so others can use it in their own stuff.
Anyway, my big regret from it is that I didn't put in enough stuff about handcarts.
I’m in a Rhine saga right now and I really recommend this book. Very professionally done. I like the digest size, which comes in at 84 pages of solid content. I learn from example, so the fact that the various rules were illustrated with examples was really helpful. The map is indeed great, and the solo play system at the back makes me want to try it. I especially loved the “potential covenant sites” sidebar, as there is more to the Rhine than the Rhine Gorge.
Rhine saga can often seem like a drag, with a gerontocracy of old magi grinding young magi under their boot heel. This book shows us a Rhine saga can be fun. You won’t be sorry. Five stars.
I am also running a Rhine Gorge saga, the aforementioned Rhine Gorge (which I love, and find super inspiring), and I find that there are a lot of good ideas. If anything, I regret not having had this book when I started it, because I like the author's addition of the Oppidium.
The Rhine map is very nice, and while I need to customise it for my own saga to include (not always canonical) chapter houses that I added, it is great addition and I will hand it to my players.
Also, with my party having established their own Covenant officially, this might well get used in the opposite direction: their Covenant seeking to recruit a Peregrinator once they have lab space.
I cannot speak to the solo rules, I very quickly skimmed them, since my own saga keeps my plenty busy with Rhine-thoughts.
Regarding handcarts: they can also be added in the digital erata...
Looking at peregrinatores from the covenant side of things - how do you attract them, what benefits do they bring, what trouble do they cause - is on my long list of possible followup work / ideas for Mythic Europe articles.