I found a great and challenging road. Brighton Rd to Sichol Swamp Rd to Lumber Rd in Croydon NH. It's part of snowmobile trail system. It's about 6miles long (I think). Some mud, lot's of rocks and hills. I went with my cousin who has a 10 JKU with 17" wheels and crappy Goodyear SR-A tires and he scraped only 3 times, not too bad. I have put 17" wheels from a 13 JKU Rubicon and I lightly scraped once. Both are all stock and our daily drivers. It was challenging but so cool. I don't recommend doing it alone. I can't figure out how to add some pics.
Not really. I open a map book and look for class 6 roads. Found some last year with varying degrees of fun. Mostly in the Tilton - Franklin area. Let me know if you find something and I'll do the same.