Roxy,

Good for you and your daughter! That sounds like it will be lots of fun.

(As for the weight loss, why are the boobs always the first to go???)

Anyway, as far as what you should bring: I always plan for poor support, meaning two full water bottles and, for a relatively short ride, one bar or banana in case I get hungry. Some people do carry some sort of first aid kit in their seat pack - I don't only because I've never encountered a situation where I've needed one. If you have, you might consider doing that.

Hopefully your ride will be well-supported and you'll only need to refill a bottle and grab some grub at the rest stop/aid station. (Just my two cents: make sure you both eat something at the rest stop, even if you don't feel hungry. You don't want to bonk down the road.)

Have fun!