Try to use the outside pump, with a fairly direct pull in and exit from the lot.
Beware of the tail swing of your camper. If you get too close to the pump or swing too quickly while exiting :E
If you approach a pump from a bit of a side angle, then swing your TV parallel at the last minute, your TV will be parallel at the pump and your camper will be a bit jackknifed away from the pump- allowing you to swing away after filling.
Essentially, you are making a "C" shape path into and out of the pump area with your TV and TT behind.
When you park in a lot and you are long without truck/RV parking spots, always park with your rig pointed to the exit at the angle you need.
People WILL park right next to you, in front of you, etc.
Had a guy pull up next to us while eating in our TV at a McD's. He pulled right beside the angle at my hitch where I couldn't pull forward to the exit.
I gave a friendly toot and waved for him to move farther away. He looked startled, gave a little wave, and moved. Many people really don't have a clue how towing works and will be in your way- intentional or not ;)
Many of the diesel stations we've been to have a wide swing, sometimes around the building path to the diesel pumps.
Gas Buddy is your friend ;)