Go the way you are familiar.
There is a four mile difference in the trip length going that suggested route, vs going straight over to US-59 from Conroe to Cleveland.
That's the issue with routing software - they think four miles is 'shorter/faster' for a 400 mile trip.
Also the 30-45 minutes 'quicker' is based on the speed limits on those roads. You are not going to be running the speed limits of 65-70-75 on those two lane roads in an RV/ towing a trailer. (Yes, Texas does have 65-70 speed limits on two lane no-shoulder secondary state highways. 75 if it has a 3 ft wide paved shoulder.)
I have tweaked my Streets & Trips for a 62 mph max, and slower on two lane roads. It shows the recommended route as at least 30 minutes longer.
There are a lot more stop lights, stop signs and fewer good fuel stops on that route than on US-59.
