First, thanks for all the helpful comments regarding changing a serpentine belt, it gave me confidence to do it myself. Here's what I can offer from my experience:
Overall, pretty easy. Just take some time to think about what you're going to do first.
* I used a 1/2" torque wrench on the tensioner (20" length)
* I uncoupled the air filter tubing, but it was probably unnecessary
* Taking off the old belt was easy by myself, just take the tension off the tensioner and pull the belt off the top pully (from the front of the truck, move your socket bar/torque wrench to the right (clockwise). Unwind the rest of the belt from the pulleys
* My last move in removing was to pull the belt through the gap that's just above the tensioner.
* As many people have said: just reverse the process. So, the first move was to squish the new belt and push the end through the gap above the tensioner (kinduv a Northeast to Southwest angle)
* Route it per the diagram on the truck, or the diagram on the package if it's there (it was on the gatorback package)
* I was able to route everything from the top of the engine compartment. I looped the belt around the pulleys by pushing and shifting the belt as needed. I did scratch up my forearms a bit, but no broken skin.
* Last, I needed to loop the belt on top of the top pulley. For this, I looped the OLD belt around my torque wrench and had my girlfriend pull the OLD belt and keep the tension on as she stood on the right side (driver side) of the truck. This let me work without worrying about the tensioner.
* To get the belt over the last pulley, I sort of pushed the belt at the pulley at about the 2pm position while rolling the pulley counter-clockwise. After a couple of attempts I was able to roll it on. No tools required.
* Checked that everything was aligned a couple of times and that was it.
Used a Gatorback belt on my 2000 F150 5.4L engine (with A/C). Picture attached.
BIG plus: no more squeakiness when the engine runs. The engine sounds VERY good!