If you don't want to travel to Arkansas, I have three notations from separate parties in the log I keep that a good auto glass shop that does repair foggy windows in the northwest Houston area is Quick Fix Headliners & Glass. You may want to give them a call before going to AR.
All three were pleased with the work and prices charged. One had a foggy side window repaired and two had windshields replaced on their diesel pushers or Class A RVs.
They are about 27 miles from Waller or about a 35 minute drive.
Quick Fix Headliners & Glass, LLC
17711 Clay Rd. Suite G
Houston TX 77084
(281) 579-3132
-----> website
GO HERE (notice in the middle of page where it says " • RV-Windshield, Side Glass, and Foggy Windows"
-----> Google SV of their location
GO HERE ...notice the DP parked in the back
ETA: actually, you might want to give them a call to see how much their mobile service might cost as they do offer that. I'm not sure if they'd go as far as Waller but you might at least inquire. Going to the other side of Houston would be more of a hassle than going to Waller so your location may just be in their service area.