Marriott St. Thomas Honeymoon

In addition to planning the wedding we are also buying a house. Planning and paying for a honeymoon is overwheleming. My finace's parents offered us a week from their timeshare at the Frenchman's Creek Marriott in St. Thomas.
Has anyone ever been to St. Thomas or this hotel?
What kind of things are there to do in St. Thomas other than chillin on the beach?