My DH's first rule of travel: "Always pack a swimsuit." Because you just never know. You might have unseasonably warm weather.
Cute story: DD13 and I didn't use the pool at HoJo in October, just the hot tub, but it is right next to the water playground. So there were some other kids in the hot tub; a pair of twin boys who were 11, and a 12 y.o. boy. All kinda cute. They were waiting for the bucket to dump, which it does about every 5 minutes; you can tell because the bell above it starts ringing faster and faster. Then they'd dash out of the hot tub and jump under the deluge, yelling and screaming. On about the third or fourth foray, they asked DD to come with, and to my surprise, she did. Then she got me to do it it, too, the next time. The other adults in the hot tub probably thought I was crazy, but it was fun.