Living Off the Grid

Getting sufficient food for a magus to survive is a simple CrHe ritual, or even a non-ritual if they have enough space for a grove.

Even setting up a lab is 'easy' through the Laboratory of Bonisagus spell.

The real question is what kind of spell or series of spells would be necessary to replace the need for lab upkeep/maintenance? I don't know what it would take to add the Inexhaustible Supplies virtue, which even then only gives a -3 to Upkeep

Well, there are laboratory supplies, which are always going to be used up and must be replaced, and lab equipment which must be maintained and replaced when broken.

Muto spells can make equipment more durable, even unbreakable. This removes the need for replacements and/or maintenance of equipment (though cleaning equipment is also maintenance, but this too can be done via Rego or Creo spells). You'll want a Room based enchantment for this.

The expendable supplies, however, are more difficult to deal with. Some stuff can just be conjured - for example, quills conjured for Sun duration are easily replaced. Ink, on the other hand, is something you want to hang around, so you're down to Creo rituals or Rego craft magic (assuming you have the raw materials) or personally having the skills to make the ink the old fashioned way. Some of this could be side-stepped through the creative use of magic; for example, instead of using ink and parchment, you take notes on thin wooden planks (made with Rego craft magic) with a magical stylus (temporary Muto effect to soften the wood, which later hardens in the desired shape).

Some consumables are really easy to conjure temporarily. For example, magical charcoal still heats things when burned. Magical olive oil still provides light when burned in a lamp (olive oil being much easier to conjure than beeswax, let alone candles). You could just conjure light and fire directly, of course, but this is a lot more subtle.

Other consumables are not so easy. Do you want to learn a spell to conjure vermilion for red ink? Or mercury for certain alchemical tasks? Probably not; the time and vis costs are well above convenience level. That said, most of these things can be purchased in bulk and last you for decades to come.

If you have magic items to do the latter, it's significantly more useful for most covenants than coal and oil (see the Improved Heating and Improved Lighting virtues in Covenants).

Aaanyway. I'd say that going off the grid probably requires automaton servants, personally - those allow you to take care of a whole bunch of needs, and it's not really possible to remove the need to have servants in the first place unless you're doing something strange. (Are your magi going to cook and clean for themselves? That takes valuable lab time and doubly so in a covenant.)

Just for clarification, by off the grid, do you mean simply alone (or with very limited grogs) and far from any town or do you also want to be mobile (like a wandering magus setting up his lab according to fluctuating auras ?) ?

Far away from civilisation and without much grog can be achieved relatively easily if you build up a good collection of tablets and/or minor magical item. With various Circle duration spell, you can easily set up ideal conditions to grow many ingredients (from animal or vegetal origin), regardless of where you are physically located. You only need to have with you a few seeds/pups/chicks to start accelerated growth.
Re or Cr Ig spell, possibly with Auram/Aquam requisit, with Circle duration will insure a glasshouse effect wherever you need it. Combined with a Circle of Accelerate growth and Blooming and you can grow anything that you have seeds/roots/fruits.
With a little bit of resources, you might consider crafting a pool of fertile soil of 10 paces diameter, one meter deep, circle by stone, magically hardened and enchanted with flying properties. Draw the required circle on the rim each time you need to grow something, speed up its growth, harvest, rinse a repeat for every item you needs, and you can even do it in a desert of stone since you are bringing the soil with you.

In this case, the magus can take time to carve into stone a proper circle around his "field" and it is unlikely that it will be disturbed. He can take all the time he needs since there is no rush and if he needs to recarve it from time to time, that's still okay, it is not like if the circle was imprisonning a demon.

You will need a few grogs with appropriate skills to turn the raw material into usable goods, but a good scores in Philosophae/Artes Liberales/Medicine, combined with the right Rego magic can also overcome that. With good Finesse and again the right spells, you won't even need Craft skill to turn skin into leather or parchment, reed into papyrus, extract salt from sea water and so on.

Similarly, a grog with Dousing virtue with a pendulum or a divining rod enchanted by a Rusticani with the right virtue can find almost anything as long as it is present in the area (various Intellego spell can do it as well).

I tried to limit myself to non-ritual based solution - the creation of some magical items can require virtus.

All in all, Mysanthropus the Lonely will need many spells, but of relatively low magnitude and a relatively broad set of skills (as already mentionned Artes Liberales, Philosophae, Area Lore (Medicine is only an option), probably with a good emphasize on Finesse (using Creo magic requires a good supply of virtus so is more Saga dependent).
It might be tricky to pull that off with a magus just out of Gauntelet, but achieveable within 10 years would be my guess: acquiring and developping non-hermetic skills is probably the limiting factor, and maybe he will have to developp a few specialty spells of low magnitude, but possibly not available from a labtext if too specific/unique.

Peregrinus the Lost will find additional challenges since he needs to be able to pack and unpack his whole sanctum, plus housing. He will need additional spells of higher magnitude and the ability to move many, many crates.
Depending on your reading of Scattering Like Light (HoH:S p 63), you can use various MuIm(Form) to temporarily change an object into his image (there was a few threads where similar spells were used to move people or even whole army, raising question about the passing of time, aging hunger and such), thus making is very easy to carry around since a book can contain all you need - just don't burn it.
Otherwise, if you find it too much of a strech Covenants has rules for movable lab.
A magical item with a boosted (larger range, faster move) variant of the Invisible Servant (maintaining concentration for safe transport) is a good investement.

What could be a bit more challenging is to keep contact with Redcaps for the ever-so-precious trade of labtext and books. If you don't offer comfortable housing and are hard to reach, they might visit you only once in a blue moon.

Of course, if you start talking about older magus, then most of these things become trivial: teleportation will allow them to go wherever they need to get what they want, and transport it back.

Just look at Marus from MoH. His entire purpose is to live off the grid. No grogs. No support. No Redcaps.

Well, for a lab, yes. But in general, the nice thing about a spell or item that creates charcoal/oil is that the product is easily broken up and distributed where needed. So if you make a barrel full of olive oil that lasts moon duration, you can light up an entire covenant with one minor item (and use the oil for cooking or defense in a siege, and it doesn't disturb any normal person who visits (though the use of oil lamps away from the sources of olive oil might seem strange, not nearly as strange a source-less illumination).

If you're living off the grid, I question what kind of mundane visitors you're going to expect in the first place.

Even off the grid, you're going to get stories knocking on your door. Far better that Johann the Goat-Herder thinks you are some kind of hermit than some kind of wizard.