Stops
1. Junction - South Llano River SP - 30A/W Dump Station or dry camping in city park along river or a former KOA right on exit 456 - pretty good reviews and looked clean when we went last August
2. Sonora - Exit 392 - Caverns of Sonora about 10 miles south of I-10 has an RV park. Good reports though I personally have not visited. 50A/W - no dump station - do not want water leaking down into the caverns.
3. Iraan - Exit 325 - About 20 - 25 miles north - three city parks - however they might be full of oil field workers.
Note - farther down the forums is a Roads and Routes section - better place to ask about specific highways.