I was looking at Google maps and ran across what I think would be a cool venture. Not much crazy off roading but more of an exploration.
Eagle mountain mine, look it up on Wikipedia. Its a legit ghost town more like ghost city out off the 10 on the south-east side of Joshua tree. I love history especially abandoned history.
I looked this up, quite an interesting history. Unfortunately, looks like the land owners have fenced and closed it.
There is so much cool history in the California deserts that I am sure it would be easy to find mining towns (Calico comes to mind, but it is very touristy) to plan an Xcursion around. I like the idea though, because I enjoy exploring history and finding weird stuff out in the middle of nowhere.
Paul has an annual trip that he plans here, The Bradshaw Trail, that has a lot of cool history (both military and early California). I think there are some postings in either Photos or Xcursions, I will look em' up and post some links.