I grew in the DFW area, and have been to SFOT more times than I can remember. It was a great park when I was a kid, and has evolved into an even greater park. Despite the Roaring Rapids death a few years ago, it is an extremely safe and clean park.
Try to go to the park when the Dallas area kiddies are in school. (For the most part, we start in August and end in May.) I believe the last time I went was in April/May of last year. There were no lines!!!! I got to ride Titan twice with minimal wait. I also practically walked on the Texas Giant (warning: it is an extremely bumpy ride, so do not go on it after eating, if your back is hurting, or if you have a headache-it will make the pain that much more worse. I speak from experience. Oh, and HOLD on tight to your belongings-I nearly lost my purse on the Giant several years ago LOL!)
SFOT also has a new Superman ride-it looks really awesome!
The only negative when going early in the season is that the shows are not up and running yet. Oh, and the park closes a little earlier.
I think
www.sixflags.com is the parks web address, so you might want to check it out before you go.
All in all SFOT is a really great park for thrill rides.
Schlitterbahn, in New Braunfels, is also a great waterpark. I've been there several times. Thier website is:
http://www.schlitterbahn.com/
In that region too there is also a cavern (I believe it's called Longhorn Caverns, and the one in Austin is Innerspace, and they might be connected) down there that you can check out if you're into that sort of thing. Also, check out Gruene, Texas just south of Austin-it has some great resturants and shops. Their is also wine-tasting too.