Just did it twice in the last two weeks. I didn't disconnect any harness, but did pull the harness connectors away from the frame in two places back near the bumper. I had to do the bed lift a second time to replace the gasket, which was leaking. I was able to access the module about a dozen years ago with out it leaking afterwards. I used a floor jack and some chunks of 4x6 timber to jack it up, and then several more blocks for safety. It's easier to drop the spare for access to two of the bolts, but it's possible to get to them without dropping the spare if you have a swivel on the socket wrench. Remove the module cap by tapping the edge with a short 2x4 block and a hammer.
Be carefull when pulling the module. It has a basket that holds about a cup of fuel, which will make a big mess when you tilt the module to get it out.
The factory manual requires both gasket and screw cap replacement when pulling the module. The cap I got with the new gasket didn't fit, so I reused the old one. Filled it up today and so far, no leaks. BTW, the old cap was white, and the new cap that didn't fit was black. I mentioned this to the parts guy at the dealer and he claimed it was the right cap.