Mine went out last week, the pump arrived today and I just finished installing it. Here's my experience: It wasn't a 10 minute job for me, possibly because of the allen wrenches I had. Took me about an hour.
I used a both a standard L-shaped allen wrench and a ratchet attachment allen wrench for the top two bolts, and the bottom bolt closest to the fender. They are kind of tight to get to, and once they loosen the ratchet can be more of a hindrance than a help. The L-shaped wrenches work, but they are hard to torque and the short end of the L was barely long enough to extend past the curvature of the pump. An allen wrench coming straight out of a screwdriver type handle might be good to get them off and start them, then torque down with the ratchet. The nightmare is the bottom bolt on the inside, closest to the engine. It's hard to reach, it's hard to see and your hand be blocking the view completely once you get a hold of it. In the thread I started when my pump went out last week someone suggested removing the plastic fender liner, and even the wheel if necessary to get access. That might be a good idea of you are on the heavy side. I'm a skinny white boy and didn't want to strip down any more off the truck than I had to, so I just worked from the top and bottom to remove the pump.
Another tricky part of the installation was connecting the quick-release hose fitting to the factory nipple. The new pump hose barb is slightly different from the factory fitting. There is a plastic squeeze fitting on the tank side of the supply line that is tough to get into the new metal hose fitting. I ended up squeezing the fitting and using a folded up Jersey work glove to press the metal hose barb into the squeeze fitting, then attached the rubber hose. The clamps were already in place and I just moved them into position. I also used a set of vise grips to work the hose clamps because the needlenose pliers recommended in the instructions kept slipping off. The 03drm.pdf instructions tell you to connect the hoses and clamps after you get the pump installed. I recommend connecting the hoses to the strainer and putting the clamps on, then connect the hoses to the pump with the clamps on, orient the hoses to match the old unit, then slide the clamps into place. Connect the tank side of the new hose to the barb (already attached to the supply line quick release fitting coming off the tank) last.
The Geno's instructions also call for disconnecting the negative battery cables. I skipped that part, though it is probably a good idea since the connection comes off the ECM.
All in all, an easy job though tight working conditions and access will be your biggest obstacles.
Good luck.