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!
'91 Toyota Pickup
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29
"They say the test of literary power is whether a man can write an inscription. I say, 'Can he name a kitten?'" -- Samuel Butler