That is a fantastic trip!
My buddy Steve and I rode Lockhart a couple of years ago. But since we were on bikes we didn't do the side trip at the Eightmile Rock overlook. Took us about 8 hours to do the 59 miles from the FR122 trailhead (basically we started at the National Park gate) back to Moab McDonalds!
"Silent enim leges inter arma." -- Cicero