The only thing I would add to the list is to emphasize that you do need to be prepared to deal with wet stuff (+1 on the clothesline). Also, if no one has said this already, put everything in some type of waterproof bag inside of your luggage.
The tour I did (Bike NC), they threw the stuff off the truck in the open regardless of the weather. Anything that wasn't in a waterproof bag got wet. (Luckily, someone had passed that tip along to me.) The spacesaver bags another poster mentioned would be great. I just used large sized ziploc bags.
If I did it again, I would have my shower stuff more organized. Maybe actual in shower stuff in one little bag, outside of shower stuff in another little bag. A bag of some sort that could hang from a hook in the shower truck to keep everything in, or at least be able to lay on the bench or chair or whatever that could keep stuff dry.
You will have a blast. Here's hoping for excellent weather for you!
Grits
2010 Trek 5.2 Madone WSD, SI Diva Gel Flow
2002 Terry Classic, Terry Liberator