I've spent months sailing around St. Martin and anchored in various places.
Ile Tintamarre - great day stop with both mooring balls and places to anchor. Beach access can be a bit difficult if there is a swell going. In calm conditions it is a great overnight stay with nothing ashore
Ile Pinel - depends upon your draft, it is protected
Orient Bay - depends upon your draft and weather conditions
Ile Fourchue (St. Barths) - mooring balls and usually pretty calm. Uninhabited island to explore with nothing ashore
Anse a Colombier (St. Barths) - one of my favourite anchorages
Gustavia (St. Barths) - busy and somewhat rolly, but it is St. Barths
Shell Beach (St. Barths) - a nice day or overnight stop
Anse a Flamands (St. Barths) - great if the seas are settled
(Skipping Dutch St. Martin)
Marigot - big and open, lots of things to do ashore
Anse a Frere - One of my favorite anchorages for day and night stops on French St. Martin. Restaurants ashore during the day, nothing at night
Grand Case - I've spent weeks anchored there. Good holding in 20 feet or less almost all the way to shore. Busy, crappy dinghy dock. But great restaurants and bars ashore.
Anse Marcel - since that is where you are starting and ending, no comments necessary