If you have a cruise port near you try that. Cruises are wonderful and can be as relaxing or active as you chose. Most lines have kids clubs. And you get beautiful scenery.
Try The Phoenician in Scottsdale, AZ. That shouldn't be far from you. Awesome and beautiful. Make sure your camera is always charged because there are so many picture perfect moments there.
I like Rhonda's Texas idea too :)
Galveston - San Luis Resort has everything you'll need with the beach right across the street. There is also Moody Gardens conference center and they have their own beach. Galveston also has Schlitterbahn and a new boardwalk.
Wild Oak Ranch in San Antonio and Lost Pines in Bastrop are 2 very gorgeous resorts tucked away from everything. They have cabanas around the indoor/outdoor pools & a lazy river, huge water slides, kids camps, golf, spa, arecades, lobbies with big screen TVs where you can watch anything, playgrounds, cafes. Both have very rustic gorgeous settings. Lost Pines offers more rugged activities but both are 5 star service and amenities. You will NOT be disappointed if you go to either!