Have driven this route many times with current Motorhome and past 5er. Both can be a pain weekday rush hours. I recommend going thu on the weekend and timing is everything. Go thu San Antonio mid-late afternoon Sat using the North Bypass loop and stay the night at the Rest Area about 30-40 miles East of SA on 10. Get up early and go thu Houston Sunday morning as early as possible directly thu downtown 10. Worked for us every time. Texas has Rest Areas as nice as a lot of campgrounds with Wifi & Security in some and far from the road noise. Good luck!
rocmoc n AZ/Mexico