They absolutely cater to the RVers. It's simply, really, RVers generally fill up, buy stuff in the store, then go away. With truckers, they have to deal with the added expense and inefficiencies of dealing with fleet fueling, showers, lounges, truck parking and other stuff I won't mention here.
But, this no-Visa at the truck islands thing is already making many RVers mad, as they can generally get into and out of the truck islands for fuel easier than they can the RV islands.
Incidentally, as someone who spent nearly 16 year in the foodservice industry, the buffet at the J is just an embarrassment to the industry. For that matter, it's an embarrassment to real food. If you order from the menu, especially whatever the monthly specials are, you're probably gonna be OK. The salad bar isn't too bad. But anything on the heated island, be afraid. Be very afraid. I can only conclude that the local Health Departments have never inspected them. I sit there and am astonished at what I see sometimes. Truly.
If you've eaten at one of them, you've eaten at all of them. They apparently have a corporate cookbook, compiled by someone who has never cooked, and all of them follow it to the letter. Including the chapter that just has to be entitled 101 Ways to Abuse A Bird. Step One - Fry chicken until it turns to pure carbon.
The philosophy must be, if a little of something is good, then a lot of it must be better, soooo, if cooking something is good, then cooking the livin' snot out of it must be just wunnerful.
They have tried to add a few healthy items to the buffet, but apparently no one in Utah knows what healthy means. The added fish, which comes in frozen and already cooked. All they have to do is heat it up and slap it out there. But noooooo, they throw it in a 450 degree oven for a few hours, lest any of that pesky moisture remains behind in the fish flesh. What you have left of something that would be much better suited for drywall applications or bathroom floor tile than for human consumption.
But again, when it's available, if you order the wild Alaska Salmon off the menu, you'll get good eats.