>>55193OP, from the general vibe I'm getting from your post, any "National Wilderness Area" will fit the bill. The most isolated and remote ones are in the northern Rockies, but those are also going to be harder to access and require planning and skills above what I think you're looking for (swimming and fishing, relaxation?).
IMO, you'll never find "true" isolation in the lower 48 unless you're willing to leave the trails. Even if you can get to Montana, and you're out in the middle of the Beartooth mountains, there's still a pretty good chance that you'll pass another human at some point in the day on the trail. Bushwacking takes a high skill level, and I just want to warn you that there is real potential to fuck up when you leave the trail, so I'd say that you should stick to local Wilderness Areas first, practice bushwacking, and see if that doesn't meet your needs for the short-term.
