I use Gas Buddy--not necessarily to search for price, although that is sometimes useful---but you can get addresses and look on Google Maps. Switch to Earth view to get an idea of the exit options.
Pumps parallel to the road is OK as long as you have space to get in reasonably straight and not block other traffic.
If you are at a larger place with pumps perpendicular to the road, use the outside pumps and you are less likely to have an issue getting out.
Try to pull forward so the trailer is not hanging out in a traffic lane. Of course that means you will block 2 pumps, but do your best to be quick. It beats getting T-boned because the trailer is hanging out.
Always have more than one CC. I've had some weird things happen at gas pumps that can cause your card to not work, or get shut down. Often the readers are not in good shape and if one card doesn't work the other one will.