You'll have fun, we've enjoyed each of our trips.
You'll need to get Permits - believe they are still free:
Staying a night in the Chisos Lodge offers great views, if you can get a reservation. The drive is enjoyable as well... the lodge itself is nothing special, it's about the location. unfortunately Winter months it gets booked quickly, but you may score a late cancelation
If you plan to stay a while, I highly recommend one of the multi-day raft trips - nothing like it.
Otherwise take a look at some of these:
This site offers some great info (use the down-arrow for options where it says "Plan your visit"
Lot of Hiking options - We enjoyed the Santa Elena Canyon Hike
Check out #6 (If you brought your passports: Boquillas is a fun day, and you qualify for bragging rights having taken the "slow boat" into Mexico - the second margarita in Boquillas is the best
) and #11 (Canoe trip down the Rio Grande is always cool
We did a couple 2-day stays in different locations as we explored the area - followed some primitive site maps. Our favorite was "twisted shoe" - for the scenery & views:
Consider some of these off-pavement campsites - some are fairly well maintained and some are 4x4 recommended - if you like to divert from the roads, be aware some of the sand is soft. If you have a heavy Van you could sink to the axles - we've manged this twice in a 4 runner with 35's. Sorry, We've been to several just cant remember which ones (and cant tell from the pictures provided
You'll have Fun!