dupersc-
The area you mentioned (clear creek/molina ghost run) is not exactly the most awesome place to go. I visited that area with Akio a few months ago, and it was VERY remote, with a maze of trails that made it easy to become disoriented. After playing there for a day I think we both decided the 2.5-hour one-way drive was not worth it. There were a lot of ATVs and dirtbikes there when we visited.
There is natural asbestos in the soil of some areas of the "park" but it's well-marked on the map, and you can avoid it if you're careful. I would guess that the dry summer months would make the soil too dusty, allowing the asbestos to become airborne.