I never use a truck stop. Why would you pay more for fuel than you need to?
I use the GasBuddy Iphone app. Usually I find diesel about 5 to 10 cents cheaper at branded stations. Only exception seems to be a branded station at the same off ramp as a truck/travel stop. Also truck stops usually charge a premium for credit cards where regular stations do not. (some exceptions apply)(also premium may be priced in).
Rarely do I run into a problem accessing the pumps. But in the rare times that I do, I simply pass it up and go to another station nearby.