My advice would be to go where you want and not worry about ATVs. Sure, you may see one once in a while, but it's a big state and the areas you're talking about are awfully remote and obscure. You're likely to be on your own out there most of the time.
On the other hand, the wilderness areas are great, there's tons of good hiking to be had in them. You can also research Wilderness Study Areas (WSAs), which are theoretically off-limits to vehicles, though those closures may not always be respected. Roberts Creek Mountain is a WSA, for instance.
http://www.nevadawilderness.org/by_area_region is a good place to start, with a good map by your side. Oddly, the DeLorme gazetteer for Nevada shows BLM WSAs, and is a useful resource for that alone, though I can't really recommend it otherwise.
Wherever you go, have fun! The Nevada outback is a great place, and solitude is very easy to find out there.
Posted: Thu Dec 12, 2013 5:08 am