I gotta say Glock 20 as well.
For the Glock, maybe it's regional thing, but they're growing on trees here. Heck, the exchange on base has a few of them. I have a 20 and a 29, both bought off the shelf with no or little wait time to order it. Glockstore.com online had them last time I checked, and the Glock supply chain has really opened up since the scare has settled down some. Ammo...it's around if you look and being in CO you can have find it online and have it shipped ground. Getting anyone to ship ammo up here is a nightmare, so I am limited to what I find in the store. But it does pop up from time to time. I just think the 10mm is such a versatile round for so many things, and 17 rounds of it in a G20 gives me a warm fuzzy in the woods. In town I carry with a standard 15 rd or the 29 with 10.
But you asked for a wheelgun. If you're gonna get a moose-stopping revolver, I'd skip the .375 and go straight to a .44. You want it to knock down an angry animal that wants to hurt you...go big or go home. If you're going to carry that heavy of a gun around, might as well make it earn it's keep. Some guys carry the 460 or 500, and that's fine. But I think a 44 is more versatile, cheaper, easier to find and you can actually take it out and shoot it and get comfortable with it before you may actually need it. For revolvers, I'm a Ruger man.