You're off to a good start. There's a lot of old west history in the museums in downtown El Paso. Then you can begin a round trip by visiting Old Mesilla, NM (history of Billy the Kid), White Sands, NM - (Day trip), spend the night in Cloudcroft or Ruidoso, NM (more Billy the Kid history) (stay at The Lodge or Inn of the Mountain Gods), then drive east to Roswell to visit the alien museum, drive south to Carlsbad Caverns, NM and enjoy the bat flight at dusk (various hotels in the area) and a day trip to swim with the fishes and turtles at the Balmorrhea spring fed pool (where scuba divers from around here get their certification) which is 30 mi. before Fort Davis, TX. Stay at Hotel Limpia in Fort Davis and enjoy an evening star party at McDonald Observatory. If you were to continue to Marfa, there's the legend of the Marfa lights at night - more UFO sightings...Then head back to ELP for your flight out; Fort Davis is around 2 hours from El Paso. Have fun!