I did it for my 97 ranger. The easiest way is to pick up the bed, so you can get to the filler tube. Remove the front four bed bolts, and halfway unscrew the back two bed bolts, but leave them screwed in part way - don't remove them. Then use a lift of some sort to pick up the front of the bed - the bed won't slide off, because you left the back bolts in. This will keep your wiring from being damaged as well. Be sure to detach the tube from the gas filler hole on the side of the bed before doing this.
Once you lift the front of the bed, you detach the tube from the gas tank, and install the new tube. Twist the tube if needed so that the other end lines up with the hole on the side of the bed. Lower the bed, then attach the filler tube to the hole on the side of the bed. Piece of cake.