Not familiar with the area, but suspect that they are referring to "dispersed camping". That's where you can set up anywhere within the regulated area, ie within a certain distance from an open road.

Doubt it is meaning a developed campground with toilets, water, etc.

Probably looking at dry camping, just be careful where you take that long a trailer, might be next to impossible to get turned around and back out.

I spent a week at the boondock area on State trust land just off the Castle Hot Springs Rd just before the pavement ends. you can see it on Google Maps in topo mode. About a 1/2 hour drive into Vulture Bait from there. There is a couple of camp sites closer to the claims but it would be a rough drag for the trailer. Best to scout first without trailer.