Do yourself a favor and remove both saddlebags completely. Pay attention to how the latch cables are routed and how the plastic clips work (for reassembly)...but it's very easy. Having done the job for the first time recently I can't imagine someone screwing around trying to save 5 minutes work by swinging the bags upward to be balanced somewhere and risk damaging them, or causing themselves a whole bunch of aggravation by being too lazy to remove BOTH bags. The mufflers will swing out of the way once loosened and present no obstructions. No need to disturb the trunk.
The links provided in the posts above should help you a great deal, but one other thing is to go to your Honda dealer and buy a tube of Moly Paste for the splines (may as well do the job the way it's meant to be done). The paste is around $10 and you'll have enough to last the bike's lifetime.
As the new owner of a 1500 and having just completed a bunch of maintainence items....this is my $.02
Best of luck!