I’ve known several people who had great experiences with Rotary. I think there is a lot to be said to being immersed in a language and culture. A million years ago I lived with a French family and studied at this program: http://www.institutdetouraine.com/en It was a great experience - I did it for a whole school year, but it’s not cheap. WOOF and being an au pair are the most obvious ways to be overseas at less cost.
I think it’s easier to apply to colleges as a senior and then defer. You probably want to apply to a college that is strong overall, so that you aren’t worrying about some obscure program that only ___ college offers.