I read a great article from earlier this year I think in Overland Journal about winter in northern Nevada and a group who went out on some really old trails and visited some really remote places. My kind of overlanding. Cold. Old. And no idea what your gonna find.
Roger Mitchell has some guide books that are supposed to be pretty good for exactly these areas. I just recently picked a couple up (Inyo-Mono SUV Trails and High Sierra SUV Trails) but haven't had a chance to use them or even read them much. I've done a lot of hiking/backpacking in the Eastern Sierra, off of pretty well established (usually paved) roads, no major Jeeping up there yet. Of course east of the Owens Valley you get into Death Valley NP which has tons of what you're looking for (and where I've done most of my Jeeping to date), though will still be pretty hot at least until we get a bit into October.
One place on the border of the Owens Valley and DVNP that might not be too bad as it avoids the low elevations is the Cerro Gordo Mine loop. It's on my list and I might do it later this fall, you climb way up to the top of the Inyo Mountains from the SE corner of Owens Valley, east of Lone Pine. Lots of mining stuff to see, including the top of the Saline Valley salt tram (which is the most impressive old mining structure I've seen, you can hike all along it down into or up from Saline Valley, though we're talking a brutal hike), and big views from way up high. Only thing is the trail may be gnarlier than you're looking for, though every trail I seem to do around the Death Valley region ends up being a lot easier than a lot of the older reports suggest, I think more people out wheeling these days tends to mean more people stacking rocks and what not, making a lot of trails easier than they once were. Can probably find some recent conditions info online.
Coyote Flat west of Big Pine / Bishop seems to be a fairly well known place, TrailRecon on Youtube has posted a couple videos from up there recently. It looks nice, although I will say I'm sort of spoiled by having backpacked the range, you can't really come close to matching the scenery accessible that way by Jeep when it comes to the High Sierra. I think this is why I tend more towards the desert with the Jeep, where you can drive deeper into the best of the wilderness. Nevada should be pretty good for that sort of thing too, I need to get out there more myself.
I spend a LOT of time in the El Paso Mtns, near Randsburg. Lots of old mines, ( some are sneaky dangerous), lots of gorgeous formations, and there is always the "Robbers Roost" areas of the Piute Mtns, just across the Fremont Pass. it is also just a skip away from the hiway to DV, and Trona Pinnacles.
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