Mustang Island State Park is pretty bare bones in terms of amenities (the rv lot is basically a big strip of asphalt with picnic tables tucked in at even intervals), but the beautiful sea coast and miles of dunes and grass are all the amenity you really need. I stayed during the week when the campground was half full and it was very quiet and peaceful. Staff is friendly and seem to like their jobs. I'm a big fan generally of the Texas State Parks system and this park is no exception.
I intended to stay at Sunset Crater National Park but then realized at the last minute that they didn't have hookups. So I turned in to Greer's Pine Shadows. The park manager was friendly and helpful and guided me into my spot. I liked the pine trees in the park but other than that there isn't anything particularly scenic or pretty about it-- it almost has a downmarket trailer park vibe due to the permanent mobile home park adjacent, but whatever, not a big deal and the park seemed perfectly safe. It was late so I didn't have a chance to check out the national forest behind the park. I'd stay again for an overnight but would try to find something more scenic for a longer term stay.
I spotted this park from the I-8 and thought it looked neat with all its mature palm trees and vintage styling. I decided to go in and stay for the night. Inside it definitely has that vintage feel: gravel lots, wood picnic tables, and patches of grass with citrus and palm trees. The palms are the best-- they remind me of old California. Lots are pretty close together but when I stayed in November 2011 the park was fairly empty. I did not try the bathrooms or showers, but I enjoyed walking around the park. There is farmland on several sides. If you stay on the North side you won't hear interstate noise. AT $29 a night the rate isn't dirt cheap but it is still cheaper than equivalent older parks I stayed in in Texas.
Peaceful spot with bonus cave tour option on long 1-10 drive
This campsite is situated next to the Caverns of Sonora ranch house, where you check in to tour the lovely Caverns (I highly recommend the cave tour). The park is basically a nice, natural, no-frills white-gravel lot with hookups (no dump site though). There are beautiful low hills all around the park full of deer and cacti. I stayed here one night on the way from Austin to El Paso. There were only a few other campers, but all were cordial and I enjoyed the peace and quiet after being packed together with other campers in Austin. There seem to be a few employees of the Caverns who live on site, so there is no feeling of being stranded in the middle of nowhere, even though this place is pretty remote (7 miles from the town of Sonora and I-10). There is no wifi supplied, but you can catch the free signal from the ranch house if you are lucky (if you need it, I recommend parking your rig close to the house). All in all a lovely stop!
I stopped here for a couple nights on the way to Austin at the recommendation of some people on the Airforums. They had said this place had a vintage feel and they were right-- the sign outside the park is really cool, with a moving roadrunner like something out of the 1950s. The staff is friendly and helped me out with a few things. I had a spot shaded nicely by trees. The park is within walking distance of some nice places to eat and sightsee: Ronnie's BBQ (people on yelp are claiming this is better than Salt Lick, but I am not enough of a barbeque expert to know), the Johnson Settlement, and a shop across the street that sells all kinds of homemade pickles and jerky. All in all there was enough to keep me fed/occupied for a couple days.
This is my first ever RV park stay so take this with a grain of salt (stayed here just after purchasing my Airstream at a dealer up the block). I've stayed in State Park campgrounds before and so was a little shocked at the price here: $54 a night for a premier site. Aside from the price everything was fine. Concrete pad was level and there were a few trees surrounding my site. I had no neighbors on this stay so my site was especially quiet (it seems that most people go with the less expensive sites farther back on the property). The owner was very friendly. There is highway noise by the premier site, oddly enough, but the farther back on the property you go the less street noise there is. All in all this was a good entree into the world of RV parking.