Places to stop along Spring Break roadtrip

The first leg of this trip Conroe to Albuquerque is 850 miles - a 12.5 hour drive.  Are you sure you want to do this?  From here to the Grand Canyon National Park is 6 hours so that's doable and you would want to be there at sunset and sunrise.  From there to Las Vegas is only about 4 hours.  But going east again to El Paso is a 10 hour drive.  Personally I would eliminate Las Vegas - that would cut the drive to El Paso down to 9 hours.  From there to San Antonio is 8 hours, and then another 3 hours to Conroe.
I'd like to suggest a slightly different route.  Conroe to Abilene (5.5 hours).  On to Carlsbad Caverns National Park (4 hours and some time to see the park), to Albuquerque (5 hours), to the Grand Canyon (6 hours), to Phoenix (3 hours - which allows some time at the Grand Canyon (do you have a place to stay at the Grand Canyon?) to El Paso (6.5 hours), to San Antonio (8 hours) and back to Conroe.