Are you looking for any gar? I have hooked up with some big spotted gar from the Shady Shores boat ramp on Lake Lewisville. You can also hike the Elm Fork of the Trinity North of 380 or South. I have caught some big spotted gar there too. Lake Ray Roberts Dam spillway always had some nice sized gar too.
If you hike South of 380, you need to go about a 1/2 mile down to the first real big bend in the river. It is a deep hole that holds a LOT of fish. The BIG gar hang out there. I have had huge gar bumping my kayak in this area before just because they didn't like me there.