Watch Hil is a really cute town that will definitely have nice hotels. Misquamicut State Beach is the biggest beach and probably the best for swimming, etc. Probably have lifeguards but can't really remember. It's close to Watch Hill.
It's Rhode Island anyway, everything is fairly close.
Newport is awesome (DS went to boarding school there) but hotels will be pricey in August.
https://maconthemap.com/2025/06/15/rhode-island-beaches/