Getting into a non truck stop fuel station is seldom a problem. We are 55'LOA & diesel. The end islands are usually the islands that have diesel, but they also have gas.
If you hang back aways because of the trailer, oh well, that's life. If the fuel supply truck can get in there, you can too.
You are not hitched to the trailer all of the time. It is no big issue to pick up fuel without the trailer. Top off before travel day or right after travel day. Easy.
Boat: 32' 1996 Albin 32+2, single Cummins 315hp
40+ night per year overnighter
2007 Alpenlite 34RLR
2006 Chevy 3500 LT, CC,LB 6.6L Diesel
Ham Radio: VP9KL, IRLP node 7995