[DonC]

Don't overlook draining the block. I get close to as much water out of the block as I do out of draining the radiator.
There are two drain plugs (one on each side) on the bottom of the block. Make sure any wrench you use to remove them fits well as I think they're brass and you don't want to strip the heads and, if they've never been out, they may be a bit stubborn.
I replaced both of my block drains with the same type of uncrewable plugs as there are on the radiator the first time I drained the system to make things easier on subsequent drains.
DonC