If you are near the border and are looking for a great place for your furry companion, Lakewood RV Resort is a great stop. It's near South Padre Island, and the border. If you're looking for a location where you can stay and experience nice amenities though, this is great for that as well.
Don't expect rustic or run down locations here. Full RV hookups, pools, billiards, and outdoor activities for all ages, but especially seniors. I can't recommend this place enough!