I guess they didn't lie, 3-4 hours is 180-240 minutes. Don't sweat it though, if you ever have to do it again it will take 1/2 the time. My 1st oil change took me almost 2 hrs. now it takes about 20 minutes, for the engine, trans., and final drive. The first time I took off the seat 1 hr. now 5 min.
I think the longest part is figuring out the "plastics" removal. Once that's understood, its down hill from there.
As stated earlier, there are location marks on the back side of the fender. I use a flat drill bit "speed bore" with small tines on the ends. Lay the fender upside down on a block of wood, once the tip of the drill bit is in the wood, it holds the position for a real clean cut, works slick.