We always stay at the Drury Inn in Corpus. It's really close to the intersection of I-37 and 358. Follow I-37 on south to downtown Corpus, or follow 358 out to N. Padre Island. The beach is best on the gulf side of the island, imo. When you get to the island, turn left at the first light, and then drive about 15-20 miles to get to Port Aransas. My family's favorite place to eat there is Crazy Cajun's. Just ask some local exactly how to get there, it's great. Back in Corpus, we always go to the aquarium, and in recent years have begun to go to the science and history museum. Both are great, and if you have a Dallas Zoo membership, you can get 50% off your aquarium ticket price. The big play ground someone else mentioned is lots of fun for the kids, too. Just follow I-37 as far south as you can, and turn right on to Shoreline Blvd., which becomes Ocean Dr. The park's name is Cole Park Amphitheater, and is on the left, bay side. Well, I hope this helps!
D.