That's the one! 75 miles, 5280' of climbing. Not "bent-friendly" but what the heck, I still think it's the best ride in Texas, though I've never finished it on my bent. Cramps get me every time around the 50 mile mark. And the steepest hills are after the 50 mile mark! Only time I've actually finished it was 4 years ago on my upright, but even then had to walk up several hills after the 52 mile cramps set in. The last time out on my old Actionbent I made it up the first big pass, about a 10 mile climb, with the last couple of miles in my lowest gear, 4.5 mph and maxed out at 163 heart rate. But didn't have to get off and walk. That climb was followed by a long, FUN, downhill, but sitting coasting for several miles was probably not the thing to do as I stiffened up a lot after the descent. If you can make it all the way around, the descent from McDonald observatory to Ft. Davis is incredible, but there is one turn that's a little tricky -pay attention to the signs telling cars to slow to 20 mph. My best friend in Midland crashed there this year and broke an elbow, but that was better than going off the side of the mountain. I'll likely go next year. It's usually the next to the last weekend of September. The website that used to have the map and profile no longer has those things. You might contact Peyton's Bikes in Midland, who sponsors the ride, and see if they've got that data and could send it your way. I've also done the Ft. Davis to Alpine and back route (50 miles). Much more tame than the loop, but still scenic with a couple of significant climbs. I'm sure I've driven the Alpine - Study Butte route, but don't remember it well. Maybe 100 miles, probably no killer climbs like the loop.
One last thing to be aware of: there is no support anywhere along the route if you're out there by yourself. No gas stations, houses, no cell phone coverage, nothing. The Cyclefest in September is well supported however. And, the last time I was there, 2 years ago, there were a lot of bents from Houston, maybe 15 or more. I passed them all going up the first pass and talked with several of them. Nice folks all!
http://www.peytonsbikes.com/