I feel your plight...I go thru this every time we travel (even if I don't have access to a washer/dryer).
On my most recent 7-day trip (Oct. 2011), which I did have access to a washer/dryer, this is what I did for my 2 daughters (DD6 & DD2) each:
-4 short sleeve shirts
-4 shorts or the skirts with built-in shorts (which DD6 ONLY wore:shrug
-1 light-weight jacket or sweatshirt (wore on arrival & departure days as well)
-1 pair of pants (stretchy-yoga-type)
-1 extra set of clothing, kept in a gallon-sized Ziploc bag (1 pair of socks, shorts and t-shirt)
-1 travel outfit (which they wore arriving & departing, & included pants, t-shirt, socks & their closed-toe shoes)
-3 pairs of socks (they usually just wore these in the evening hours)
-4 pairs of undergarments
-1 blanket
-2 sets of shoes (1 pair of sandle-type, for by the pool as well, & the closed-toe-type)
-1 sun-hat (one of those swimmer hats made out of the same material as "rash-guard swimming tops," which I could soak in water if it were too hot out)
-1 pair of sunglasses
*Seriously, kids clothing does not take up that much space, so that's why it seems like I packed a lot. Plus, I'd rather over pack for my kids in case of an "accident" or if I don't have the time to do a load of laundry.
I still ended up buying each DD a t-shirt and pant set, which would bring the total for outfits to: 7. And, I did do two loads of laundry for my family of 4 (once mid-way, and quick at that, & the second the night before we were leaving).
Enjoy your trip!:wave: