We get there on the 14th and I just mostly finished packing for me and the kids (my husband lives dangerously and packs the night before...or just before we're leaving the house...I think you can guess which one of us does the vacation planning).
I checked the weather forecast and it all looks pretty warm and fairly dry for that week, I bet we'll be in shorts and t-shirts 95% of the time. Coming from the Midwest, 60 still feels pretty warm to us.
I have ended up doing laundry every trip we've done, but I'd rather not have to do it.
Because we're staying off property for our first night there (getting there late after a long drive), I pack one duffel bag that holds all of our stuff that's needed for one night, so we don't need to totally unpack and repack the whole van - PJ's, toothbrushes, hairbrushes, complete change of clothes for the park the next day...even though the weather says it will be warm I packed us all both shorts and jeans, but a short sleeved shirt, and we'll travel with our windbreakers and sweatshirts in the van, just in case).
I also packed robes for the kids to wear after swimming because they're horrible at holding a towel on themselves, and for them it's a cold walk back to the hotel room after swimming.
We usually buy sweatshirts and stuff like that anyway, to bring back with us, but I hate needing to buy something quickly and then getting something that I wasn't really thrilled with.