switters

I'm going on a book tour in early January. I'll be on the road for about 3 weeks straight. Obligations will include signings at bookstores, local media (radio & TV), presentations/lectures, and informal gatherings (e.g. dinner with friends in various cities, etc.). I'll be visiting 13 cities during this period, and some for less than 24 hours so this will involve a lot of flights (in the dead of winter, no less)! For that reason, I'm trying to figure out a way to avoid checking a bag if at all possible. I've never done any extended business travel like this so I figured I'd ask for help from those that have.

I can imagine needing the following clothes:
— Sportcoat
— 2-3 shirts
— 2 pairs slacks
— 1 pair dress shoes
— 1 pair athletic shoes
— 1 pair pants & shirt for working out
— Several pairs socks (most dress, 1-2 casual/workout)
— 1 casual outfit for informal gatherings and travel?
— 1 down jacket for weather

As I write this list it seems impossible to do this without taking a larger bag. I have a nice Briggs & Riley 22" expandable carry-on which is about as big as they get, but I don't think I could fit all of this along with toiletries and other items.

There's also the question of how to make sure I have a clean/pressed dress outfit when I arrive in a new city if I only had 24 hours in the previous location (which may not have been long enough to have my pants/shirts dry-cleaned).

Any ideas?