Yep, unfortunately I'll need at least two. The business attire situation works a little different for ladies.
Here's what I do.
PACK:
. One good quality BLACK slacks or skirt (your preference - for me, it's slacks)
. 2 blouses that can double as light jackets - overblouses particularly good, especially if silk
. 2 camis that will work with the blouse/jackets
. Black stockings
. Black court shoes
. 2 sets of undies (wash as you go)
. 1 casual top
. Night attire that can double as cover up for pool etc. Having been caught once very badly when I had to leave the room in a nightie, I now wear only "resort PJ's" at night.
WEAR:
. Black overcoat + cardigan +++
. Black slacks + casual top
. Black casual shoes + socks
. Carry and change into ballet slippers. The slippers give some protection against what might be on the toilet floor. Also good for hotel rooms etc.
Be prepared to wash undies.
Learnt this many years ago when I used to work with fashion designers who regularly flew ATW. One lady would do 2-3 weeks with carry on only. Her philosophy was: One on, one in the wash and one clean. Had to go suppliers, then onto the opera at night so a number of looks - but always based on black.
Good luck