Of the five state parks we have visited, Eisenhower State Park, located on Lake Texoma near the dam in the Red River, has the best trails.
There are enough ups and downs and twists and turns without being too daunting or boring. They are also shady for the most part. We were there Fourth of July weekend which was a little over a month after the record Memorial Day rains that despite continuous flushing through the dam, kept the lake 20 feet above full. Therefore the boat ramps and swimming beach were all underwater. Very nice hiking is enough of a reason to go anyway.
In the hot afternoon we got in the car and drove to the other side of the dam where we watched the massive water canons shooting out white water rapids which apparently contained a lot of huge bass that were being reeled in one after another below.