I did Cedar Breaks to mile marker 3 and back last year (not as much solitude there), but this time I started at Tejas Camp and went to Sawyer Camp and back. (Plus a detour down a jeep trail between mile markers 9 and 10 where I discovered a secluded camp site in some trees near a creek/drainage.) It ended up being around 8.5 miles.
Tejas Camp looked pretty nice, a good quiet place to camp if you don't need amenities (like showers). Depite it being a gorgeous, not-too-hot weekend, there was no one there. The toilets are adequate and there's water. Some of the camp sites are near one another, and others are more secluded. Most were shaded.
Sawyer Camp, on the other hand, was a mess. If they're not going to fix up the old toilet structure, they should just knock it down--it's an eyesore. Several of the fire/grill pits were broken and/or overgrown with grasses and vines. There was litter scattered around. The one picnic table there was OK. The lake level was low, and if you needed to go down to pump water, you'd have quite a trek. I saw only one, maybe two camp sites that would be worth pitching a tent in, and that's being generous due to the lovely solitude.
The trail itself was pretty good. Lots of varied terrain, switching from open fields to wooded sections to rocky outcroppings. I only saw a couple of other people the whole time. There were some sections where grasses have grown over rocks on the trail--it would be easy to twist an ankle or crash your bike here.