[NevadaWolf]

Originally Posted by Zombiphone

(I'm planning to camp at the national parks for my accommodations this trip)

If this is the case, definitely the NPS pass will come in handy (http://www.nps.gov/findapark/passes.htm) and it even covers parking for other agencies - like the Sandia Peak I mentioned.

And you are picking up a Passport book, right? http://www.eparks.com/store/

Both of those are available at almost any park headquarters/visitor centers, just linked so you knew what I was talking about.

I'll post a suggestion that @cuong-nutz offered me when I passed through Texas, hope he doesn't mind me quoting him.

Originally Posted by cuong-nutz

I would suggest hitting TX-118 to Fort Davis and then take TX-17 North back to I-10. This will set you back an hour but that may not work out to your favor. It's really scenic and twisty but you're out there in the outskirts of the mountains. It's east of Van Horn which is east of El Paso off I-10.

I know a definite route for you before you come into Houston. FM 1458 from I-10 to San Felipe to 359 out in Brookshire will put you back onto I-10 heading east. It's a scenic route with sweepers and will break away the buzzing of slabbing it for hours. It'll take 10-15 minutes off your route.