Welcome to Mustang & Padre Island Beaches
The rest of the beach is administered by Nueces County. There are access roads every few miles, and most have a parking area; parts of the beach are blocked off so that inattentive drivers in 4WDs can't mow you down. Sand dunes back most of the beach area. Only since the 1970s have some monstrous condo developments appeared on Mustang Island near Port Aransas; otherwise most of the sand is blissfully undeveloped.
For most of the beaches you'll need a permit to drive on the sand. However, a 6-mile stretch just north of Padre Island National Seashore is free.