I always fill up where the RV can get in and out without issue. This, to me, is much more important that the price. I do price shop but I am not going to go way out of my way or to an unknown scenario to save 20,30 or 40 cents per gallon. I use truck stops for my 40' RV towing a car. Generally that means Pilot/Flying J but I will also visit a Buckees's or similar station if I know I can get in and out easily. The Flying J just E of Houston is something like $2.61/ gallon while the Buckee's was $2.12. The pumps at Buckee's cut off at $150 so I had to use my CC twice and the pump volume means you are going to be there a bit longer than you would be at a Flying J pump but I am OK with that condiering I am saving about $50.
On the other hand, If I am traveling cross-Country trying to get from point A to point B as soon as possible, I am stopping at Pilot/Flying J every time. Easy in, easy out, dump, water, overnight parking, good food, cash price even when using a CC plus the PFJ RV discount. Yes, they are more expensive but in many cases this is a service I am willing to pay for.