My 2 cents
My first choice on the highway would be an Exxon, Shell or other brand name (at a truckstop would be a plus). Next choice would be a place that looks like it turns over a lot of fuel. If they don't turn over much fuel there's a chance of water, etc settling out of the fuel, especially diesel. I usually qualify this method by price first; i.e. lots of times the diesel that's a few pennies cheaper will turn over more fuel. Lots of times when I pull into a town that I haven't been to for a while or while going through a new area, I'll go a few miles past the first few stations I see and the price drops somewhat closer to the 'inner city'. I don't do Diamond Shamrock, Valero, Fina and a few others similar to those for the most part, due to the way they refine their fuels and the filtration methods they use at the fuel pumps. I've had injectors plugged up on a number of occasions from supporting their operations. It may have been location specific problems as opposed to the brand name but I'm not willing to chance it. Injectors, etc can be an expensive repair - much more than the few pennies I saved per gallon plus the hassles of having to get the repairs done. It may just be my experience so far, but it seems to me that FJ is usually a little cheaper but I don't get very good fuel mileage from filling up there.
Now for food, it seems to me that the farther north I go, the more food loses its flavor. In south Louisiana, almost every little one horse town has convenience stores that have the best plate lunches around. In Texas, its tacos. As for the chain restaurants, I like Saltgrass Steakhouses that are now branching out of Texas. Next choice would be a good Hooter's Restaurant - but of course I love the 'Wings"!!