If you are looking for something other than the State Parks and want water, consider some of the areas around the Army Corps of Engineer lakes.
Here is a link to some trails around Lewisville Lake and Grapevine Lake. I would particularly recommend the Northshore Trail on Grapevine Lake, although you will have to watch out for bikers.
Edit: The lakes are very low due to the drought. Both Lewisville Lake and Grapevine Lake are about 7 feet below the conservation (normal) level. Most boat ramps are unusable. We were on the Elm Fork trail this afternoon and were shocked at barren some of the shoreline of Lewisville Lake looks. I suspect that will be less of an issue for Grapevine Lake, but it may be less picturesque than normal.