Never been to Thomas, but the top of Santa Rosa Mtn / Toro Peak is pretty nice. Not sure if it's still there, but there is a nice spot on Santa Rosa at an old cabin with a fireplace chimney. About 8000' with views of the Borrego Springs desert...
I have only camped up there once but it was north east of Toro Peak. Does anyone have any recommendations? This spot as I recall is able to handle a number of rigs. It's at the end of a 2 track. That last time I was there was with Harley...