You cannot leave your boat at Founders Park.
As far as a motel, if your wife is coming, she should be the one to decide on the motel. I would not presume to make suggestions, because my needs are pretty primitive.
If you want a place where you can stay and keep your boat and sail from an actual beach, check out the Key Lime Sailing Club,
www.keylimesailingclub.com But I'm sure the accommodations aren't Hilton category.