The easiest way is to remove the frame. The shop book calls for rotating the motor, but I feel that the added work of just pulling the frame off the motor is minimal compared to the amount of access given versus a rotate.
I've done it without rotating the motor, but its a lot of aggravating work, especially due to the very limited space available to fit a wrench (or a hand) in. I wound up cutting down some old 1/2 wrenches and 1/4" allen wrenches to get in there easier. I also picked up a long T-handle allen wrench with a ball end that I find helpful as well. There is also an offset allen wrench, sold at Harley stores that comes in handy as well. I recommend using stock Harley seals if you go this route, as the James "blue gaskets" with the lip are tricky to fit in and line up due to the limited space. There is a youtube video by NCCR that shows the weird variety of tools they use for removing/replacing the allen bolts. Some people have also used really stubby or curved 1/2" wrenchs for the size with the hex bolts. "Luckily" these tend to be easier to remove due to the hex shape that you can almost get a grip on.
If you dont rotate the motor or pull the frame, its going to be a lot of, figuring out what tool to use to get on the bolt, turn is 1/16 of a turn, remove the tool and look for another tool to turn it another 1/16 of a turn. And after its all done, you'll probably swear that next time you're going to pull the frame.
Its going to be at least 3 hours each way, especially the first time. RidetheLightning just did a rotate a week or so ago.