The Royal Islander Great Bay is the timeshare arm of the Sonesta Great Bay. Some one TTOL is an owner I believe and will probably chip in.
We’ve stayed at the hotel part for a couple of nights in Jan 2014. Easy walk to Philipsburg during the day, not so safe to do so at night. We looked at the TS units, so called Miramar wing. Private sundeck, pool and whirlpool, but you also can use the hotel facilities which we were OK
A flaw for us was no sunset as the hill gets in the way, but otherwise workable location
Link shows the unit floorplans
http://www.royalislanderclubgreatbay.com/accomodations/

J&B