There are a lot of places to hunt waterfowl in N Texas. The caveat being there are 50,000,000 duck hunters in N Texas. If you want to treat your father and girl to a memorable hunt, there are some great guides in our area. If you want do it the old fashioned way, get the APH public lands book or better yet hit the TPWD website and search for public hunting. It has a wealth of information on area lakes, rivers, and WMA's that allow the hunting of waterfowl.
I'm sure you know this but I'll say it anyway. Scouting water, putting in the time and effort to find birds and learn the lay of the land, will give you the knowledge you're seeking. If you don't have the time or the patience, a guide will give you plenty opportunity to shoot a duck. Oftentimes witha better chance of success if you have a limited of time.
Do you ever get the feeling you're being watched? Because if you do, I'll stop doing it.