I suppse there are several ways to do it but I either do one of two things.

Use a dubro quick fueler on the side of the fuse. 1 line from muffler to tank. 1 line from carb to quick fueler to tank. If the muffler is inaccessible to remove the pressure line when filling the tank, I add a third line for fueling and cap it off before flight. (If the third line is done, I make sure there is a way to clamp the carb line so I don't flood the engine when filling)

Or If not using a quick fueler of some sort, I'll run one from the muffler to tank. Another line from carb to tank. The car-tank line is cut and connected with a brass tube. This line is place in an area I can access it to pull it apart and fill the tank.