I have a 41 foot fifth wheel and a 23 foot long dually pick up truck. Combined (hitched), I am just shy of 60 feet. I have never had problems getting diesel at normal (gas station) service centers. I do NOT do truck stops. They are dirty, grimy, oil spills in the fuel bays, and the price of diesel in every state is something different, especially Indiana that has "exempt" and "non-exempt" diesel. When pulling up to a truck stop diesel pump, it's too darn confusing.
For all these reason, I stop at only normal gas stations that advertise and sell "auto diesel". Being 60 feet long, I've not had any problems getting in and out.
BUT! I also select my fuel stations carefully too. Some are just impossible to get into, even with a bicycle!
The secret to the success is to fill the tank when it is only half full/empty. Start looking for a fuel station at about 1/2 a tank. Do not even THINK of getting fuel in a city or larger town where turns are tight and bay areas are short. Avoid filling up in suburban areas.
Use Gas Buddy on your phone. It shows a map of your current location and where the closest fuel stations are located, based on your selection (gas or diesel) along with the last known price per gallon at that station.
If traveling, we'll give the most logical one a shot. However, if when actually getting there we find out the lot is just too tight, we have no qualms about moving on. There will be another station up the road a little farther.
We've never, ever come close to running empty doing it this way. So, selectively choosing the stations is what makes it successful to fuel up .... gas or diesel.... a motorcycle or a 60 foot rig.
Also, having good control of your rig, knowing how to back up, knowing how tight of a turn, and knowing how to maneuver through tight spots makes using the more "tight" stations very manageable too. It just takes a little patients and a little tolerance for other inconsiderate drivers to successfully navigate some of the tighter service centers.
What does irk me is when a "normal" gas station has only 1 pump for diesel. I'm sitting there with my 60 foot train waiting for someone else using the "gas" side of the same pump, when there are 10 other pumps sitting empty. So, I wait patiently, and in a position so as to not block traffic any more than necessary. After the person gets done, goes into the store and spends 10 minutes and walks out with a coke and a bag of chips, talking on his cell phone, he FINALLY pulls away. I now begin move forward and before I can get up there to the pump, someone other soccer mom driving in her little grocery getter SUV whips up the same pump, jumps out and runs in the store and doesn't even get gas. So, now I am sitting in a position where I'm blocking traffic. And now I'm really irritated. So, my best retalliation at this point is to simply move forward with my 60 foot rig and block everyone. When Soccer Mom comes out of the store, she's now pissed because she has to back up to get out of there, and she doesn't even get gas, but give me the nastiest, dirtiest, more horrific look on her face as if to say, .... "If I only had a knife, I'd stab your eyes out!"
That's the one thing I do not like about the smaller service centers.