Gunny, a couple of things:
First, if you can get to where you need to be by taking out the bed bolts and raising either the front or port side of the bed, you'll be WAY ahead compared to lowering the tank.
Secondly, if you MUST drop the tank, let me tell you what I had to do:
Disconnect filler neck/vent pipe assy; drop rear driveshaft and carrier bearing to access the hose and electrical connections on the tank module and the front strap bolt; and bear-hug the tank while using a sharp putty knife to cut the adhesive holding the tank to the upper crossmembers.
As I said, if you can, raise the bed instead! Semper Fi!