It is a bit easier to drop the take when the rear bumper is off.
So I say, take off rear bumper, remove the gas tank skid plate, the two strap that hold up the tank are attached on the tail pan. Lossen the nuts ALMOST all of the way to drop the tank a bit. Then get betweent he tank and floor and remove the filler neck hose and fuel lines. Then support the tank and take the staps all the way off and the tank will drop straight down. If you have a frame-mounted hitch, the skid-plate can be a bear to wrestle around...
and get as much fuel as you can out of the tank before you drop it...Not only does it ad weight, but when you still have like 10 gallons sloshing around, it can make things interesting when you are doing it by yourself...
Chris