this is what we run into when traveling with the 5er.
Most newer gas stations now put the pumps facing the building. This mainly sell gas and food, not mechanics. When going to these, we go to the end pump put only after making sure we can get out. If someone is already there, we have to wait.
But we have found that small towns have a good mix of the older gas stations that aren't major food venders. These usually are great for 5ers, and MH as there don't have rain covers overhead. They usually have 2 entrances which make for easy in and out.
I second the idea of not filling up during the morning rush. We try to fill up a couple of hours after we head out. This adds a nice break to the morning drive.