6 days...1 to get there and 1 to get back, assuming you are driving from Dallas.
Leaves you 4 days and a lot of highway to cover.
1.) Stay @ the Gage in the Los Portales section (Marathon) at least one night. Booze it up at the bar and have a tequila under the white buffalo head mount. Great pool and the Gage manages some private residences in Marathon that they will rent out. Some are quite nice.
2.) Drive into the park from Marathon and go to the Basin area. Call now if you want to stay in the cabins and or the motel in the Basin. They're prolly already booked, however. If they are, Lajitas (40 miles SW has places to stay).
3.) In the park you can sweat on the desert floor or sweat while hiking the South & East Rims or sweat while going up to Emory Peak or down to the Window. The Window is the shortest trip. Emory and the South & East Rims are fairly strenuous hikes that can take up to 5 hours or more...one way. If you are staying on the "rim" at night, you'll need food and lots of water and camping gear. Not small child friendly. Teenagers will be OK. Same for Emory except you can't camp on the peak itself and the last 100 or so feet is straight up a rock face and freaks out some people.
All of the upper hike trails (Emory & South and East Rim) will be littered with fat, salt-eating, water-retaining pieces of cheese that are hiking up hill, about .0025% of the way there with 1/2 a liter of Evian, sunburn kids and big pulsating blisters bulging from their Birkenstocks asking how much further it is to the top. Don't be one of those people.
It does get cool at night (even on the desert floor), so bring a jacket.
You can overnight truck camp at a primitive site. I suggest the Ernst Tinaja site off of Old Ore Road (dirt road)in the desert floor. Pretty cool site with a very short hike to the tinaja. Head there late in the afternoon so you don't get all burned up in the heat of the day.
You could head to the Hot Springs on the Rio Grande River in the SE section of the park and, well, get in the hot springs. Its not too far from Ernst Tinaja. Only advisable if its cool outside.
While in the SE part of the park, don't bother going to Boquillas de Carmen in Old Mexico. It used to be fun but it ain't now. Just listen to Gringo Honeymoon and act like you went.
3.) Terlingua Ghost Town....Starlite Theater and La Kiva are good watering holes with food. La Kiva has pay as you go showers if you've been hiking and need to dewsh. These places are in the SW part of the park.
4.) From Lajitas you can take the Camino Del Rio northwest to Presidio. A great drive with a bad ending in godforsaken Presidio. part of the film "Fandango" was shot on the Camino Del Rio at the top of the main grade when they went to get "Dom." The view of Tex, Mex and the river is extraordinary.
Big Bend State Park is out that way, too, and you might get a place to stay at the old Sauceda Ranch HQ. The ranch HQ is 30-40 minutes off the highway in a very remote part of Texas. They may still do all day horseback rides that are pretty cool.
You can raft Santa Elena canyon. You get in the raft and the guide rows you down the Rio Grande...if there is any water. You get lunch and lounge while someone else works....not a bad deal. If the river is slow it can get a little boring but the views are great. If the river is fast it can get a little crazy but not over the top for kids.
5.) You can go to Alpine and Marfa which represent the big city in the area. You have to see the Marfa Lights if you go just so you can get all weirded out and commune with the crystal rubbers and burn-out hippies and see the lights.
6.) Fort Davis has the Observatory and, of course, Ft. Davis its own self.
7.) Wanna blow some money and quick....Cibolo Creek in Shafter (b/t Presidio and Marfa)....I mean real 5 Star stuff in the middle of nowhere. You might get lucky and run into Mick Jagger there like a friend of mine did...talking about getting weird...what's up Jag! They also have houses for rent there. Some of them are way out and you could have your own personal ranch for a day.
In general, the area is immense and takes some time to cover. If you try to do EVERYTHING you'll ge in the car quite a bit. I've been there about 10 times. Sometimes just driving and stopping for drinks and somtimes staying and hiking for 2 or 3 days.
It is a really cool place that you can't describe unless you've been there. It ain't like the rest of Texas
Our forefathers had civilization inside themselves, the wild outside. We live in the civilization they created, but within us the wilderness still lingers. What they dreamed, we live, and what they lived, we dream. -T.K. Whipple from The Study of the Land.
[This message has been edited by KeepItLow (edited 1/7/2009 4:15p).]