Cleburne State Park has some great trails. Good mixture of easy, tight and twisty in the trees, hard pack dirt trails, to lung busting climbs with rocks and roots, creek crossings. Probably +/- 15 miles of total trails. Riding the 6-7 mile 'outer loop' will work you more than the mileage would indicate. Then there's the small spring fed lake ( low due to the drought ) that you can throw the kayaks in and paddle around to cool down after the ride. Nice camping areas to choose from as well. Then, 20 miles down the road you have Dinosaur Valley State park that has similar terrain ie; rocky/ rooted/ lots of limestone creek beds/ wide open spaces and moderate tree cover/ good climbs and downhills but has a bigger feel, better and very scenic! The Paluxy river runs through the park but not really enough water to kayak. So you could easily stay and ride Cleburne 1 day, get up the next morning, a short 25 minute drive west, and you could ride Dino. Valley the next!
Tyler State Park would be great for out east. It also has great trails though not as technical as Cleburne or Dino. Trails are tucked under the canopy of beautiful pines with sandy winding singletrack. Also has a small lake for kayaking and really nice campgrounds all in the pines.
You can't go wrong with Reveille Peak!! I don't like to use the term epic, but...the trails there are quite extraordinary. Nothing like it around these parts.
Colorado Bend State Park also has some killer trails, although I've only ridden out there once and did not ride it all! Very scenic and you have the Colorado River, but not sure how low it is or if you can kayak at this time. A phone call to the park rangers would help!
I've never cycled Palo Duro Canyon, but looks like it would be awesome. I haven't been out there in years but It's on my short list to ride there!
Sounds like a great trip ahead wherever you wind up, have fun!