I love Big Bend!
Thanks to DevinSixtySeven for pointing out this thread to me!
My family and I have taken several trips to Big Bend. We have a bunch of the maps and have had more fun than should be allowed (in fact, we have had more fun than was allowed once, but that is another story and $400 lesson - stay out of the arroyos on National Park turf).
There's plenty of awesome hikes, some fun 4x4 trails, and some of the most amazing environments on earth there. If its OK, I'll keep the dates open and see if they work out for my son and I. If so, it would be kind of a last minute thing.
Some of the better hikes are near the Basin area. Our favorite is Cat Tail Falls. You go from arid desert to botanical gardens in two miles or so. If I remember, its on the west side of the Basin where "the window" allows water to drain out of the Basin. There's another oasis on the east side, but I can't remember the name. I'll look at our maps and post that one up later. Another cool spot is Earnst Teneja. Be sure to look at the sides of the pool if you go to that one.
As long as it isn't wet, a great 4x4 trail is Black Gap Road. It is un-maintained, and the wetness is really only a factor crossing two arroyos if there is rain. There is a great 35-45 degree rock to climb on that trail, too.
I hope it works out that we can join you guys.