If you are driving directly to GP you will need to pack breakfast,lunch,& dinner cause there is not sheet for 50 miles to the east and 100 miles to the west.
Carlsbad is the only place I know where there is BBQ that is anywhere close to Guadalupe National Park. It is on the right hand side (in Carlsbad) as you are heading north from the park. I would suggest also looking in Van Horn to see what they got since you are coming from the sothern root.
Make sure you check out McKitrick(sp?) Canyon in the park. You will not believe the foliage and scenery for that area of Texas. Ask the locals in Carlsbad about the Mexican food-they should be able to direct you to the best spots. I do miss West Texas mexican food!!! Midland has some of the best places for Mexican food!!!
Chuy's in Van Horn is recommended by John Madden. They always have his table set. Did eat there for one post GP summit celebration. Much better choices back in Midland/Odessa.