Of the three you mentioned, I would probably buy a .357 Maximum from MGM. You can load it with .357 magnum brass, according to Mike Bellm, and can do so with carbide dies or a Lee Loader. And you can shoot .38 Special wadcutters in it during the off season for practice and small game, and get really expert with it.
Either the .30-30 or the .35 Remington would work fine. So would the .44 magnum and the .45-70, for that matter, or the 7-30 Waters. No bad choices here (except maybe the .358 Winchester, a great cartridge but probably too much for the G2, sorry War Eagle).
