Welcome to the forum. (Like I'm such an active member.)
I would thoroughly cut the bed liner material out from around the washers. You should also remove all of the material from the inside of the Torx head. You want the bit to fully seat into the bolt. You should also spray penetrating oil on the bolt threads several times at least a half an hour before you break the bolts loose.
I recently did another one and I followed the same method that I posted earlier with the exception that I lifted the bed up with my shoulders and put the 4x4 piece in by myself. The bed is surprisingly light when just one side is lifted.
Put the rear axle on jack stands and remove the left rear wheel.
Remove the gas cap and the three small screws that hold the filler to the bed.
Remove the three bolts on the drivers side of the bed with a t-55 Torx bit.
Loosen the other three so that there is about a half of an inch between the head and the bed.
Lift the side of the bed and place a piece of 4x4 on the frame rail to hold the bed up.
I also removed the inner splash guard.
Remove the hose clamp holding the filler to the tank. I used a 1/4" drive 5/16" socket and a ratchet. The clamp is molded into the OEM hose, loosen it thoroughly. The hardest part was pulling the crusty hose off of the tank.
Use anti-seize or grease on the bolts to make future removal easier.
Good luck and be safe.
Very useful information guys.
I will be removing my bed to replace my filler hose but the bed in my truck is spray in. Any tips on what I can do to make removal easier?
Thanks!