Thanks for the input everyone!
We're in Olympia. This location has 25 members right now, and 8 total boats. It appears from our visit and their answers to my questions that getting a boat will not be a problem. I think we're going to go for it. I'm just going to double-check that we'll be able to extend our 12 month commitment to the end of next summer instead of another 12 months at the end.