The beach at Matagorda runs for miles and is basically wide open. North Padre Island runs south for miles and is the same way.
I've driven my Jeep on them many times and as long as you are not right AT the entrance areas, I would say you can let your dogs run.
If you go down to the beach at High Island and turn left, you can go a short distance and do the same thing. There IS however a hippie hollow at this beach.
