T.O.
A 3 year old doesn't necessarily need to go that far to be satisfied. Lake Grapevine has cabins on the Grapevine side, not far from Main Street. The Vineyards Campground is the one to check out. A camping cabin is a lot easier to get into than a tent.
http://www.vineyardscampground.com/
Glen Rose has Fossil Rim Dinosaur Park Campgrounds.... I don't remember any cabins there, we did tents and there was wildlife and a stream but we didn't fish so I don't know if you can or not there. You can find dinosaur tracks though!
If you want to go a few hours and see some great wildlife and different hills, go to the Ouchita Mountains in Oklahoma.
http://www.fws.gov/southwest/refuges/wichitamountains/
FYI many of the lakes are down right now, so fishing will likely not be good.