Thunder Mountain Trail is just outside Bryce Canyon National Park. The first section has more climbing than we expected after consulting the MTBproject website and less scenic, but the descent among the Red Canyon's hoodoos is a blast as we ride along knife ridges and switchbacks back to the trailhead The last mile is a super fun let-the-brake-go flowy downhill. The trail is mostly smooth hard pack but has short serious sections of loose, steep, switchbackery madness (probably the reason why it is rated as a black trail, because most of it is truly blue). There aren't much in the way of steps or drops, the technical sections are short and walk-able with the climbing mostly moderate. What makes it harder is that you are riding at over 8000 feet of altitude and you sometimes wish you had an oxygen mask on while climbing.
If possible, ride this trail from the upper trailhead to the lower trailhead, with a car shuttle back. Several sections of the trail are virtually unrideable in the uphill direction.
However, riding the trail as a loop is possible if you ride back up the bike path for 8-9 miles.