This winter there were several of us Heartlanders staying at Cottonwood RV Park. It's nothing fancy, but has FHU, & a laundry in the clubhouse, and the price was real reasonable, a lot cheaper than some of the other parks & you weren't right on top of your neighbor. A lot of the parks down there have activities in the park, and some even have bands, etc. come into the park. About the only thing Cottonwood has is on Wednesday we would meet at a restaurant, for breakfast, and that evening those that wanted to would play bingo. Most of the parks that would have bands, etc. in the park anyone could attend for a fee. We've been in several of the parks down there and some of them are real tight. Sorry, off the top of my head I can't remember the names.
HERE is a link to some info for the RGV, that also has a list of some of the parks, it's under the tab
Winter Texan communities It's got them listed by city, and there is also a map. There is always something going on down there. Also if you are interested in going into Mexico, most everyone I know of crosses at Progresso, and I really haven't heard of any problems there, be sure to bring your passport.