Big Bend is one big ass rugged park. Not as pretty as some other national parks and I've only been there one time but there is a wierd spiritual vibe about the place.There are some hot springs in BB right on the edge of the river so bring your speedo. Personally I wouldn't do any backroading by myself because of the desolation but thats your call. I'm guessing there will be plenty of riders there to hang with. When in New Mex look up Buls4evr. He's a very good rider..... considering his age..
.. and probably knows south N.M. better than most. There are a number of roads that go south from I-10 to 90 but one I've wanted to explore is just a couple exits west of Sonora. I don't know the road number but I think it goes by the Sonora Caverns? The Caverns are a great place to visit so take the tour. They are beautiful caves and well worth the stop. Make sure you fill up in Sonora because gas might be hard to come by between there and Langtry.