On UT 261, about 13 miles south of UT95, almost a mile past milepost 20 turn left on Cigarette Spring Road CR239 just opposite Government Trail Road. Pay your fee at the trailhead about 1 mile in and continue for 2.4 miles to a spur road on your left. Go north for a few hundred feet to a obvious pullout. Follow the well-trod .3 mile footpath taking you to an entry point into a side canyon. Descend the steep slop to this side canyon. Contineu E-NE for a whle until the side canyon meets Road Canyon. Make sure you mark this junction and turn right into Road Canyon. A few hundred yards from the last turn a tall hoodoo will come into view on the left side. Start looking up from this point at the ruin is 100 feet up above the canyon floor.
Take water and a gps with you on this hike. Mark your car, the beginning of the trail and your descent point into the canyon and your right turn down Road Canyon. It is not hard to get out of the canyon but the first .3 miles of trail that you started on has many cross paths and it's easy to get lost on the way back. Many 12 feet tall scrub juniper will block any view of the parking area and they can be disorienting.
Fallen Roof Ruin is in Road Canyon which contains some remarkable Ancient Puebloan dwellings.