As RonDon says, you'll find more sailors over here https://www.traveltalkonline.com/ubbthreads.php/forums/7/1/british-virgin-islands.html but I did a two week out of Anse Marcel earlier this year. I presume you are with Dream Yacht? The base and staff is very good although a lot of the surrounding property was closed. Orient Bay was a horrible anchorage the one time I tried it on a previous trip. It is open to the prevailing winds so lumpy and uncomfortable most of the time. We didn't go to Anguilla this time although have in the past and love Road Bay. However, in my opinion, it isn't worth paying the horrendous fee to cruise the rest of the island.

This trip, we were on a mission to get as far as Montserrat so didn't stay around SXM for very long. With the short time you have I'd head down to Grand Case or Marigot and anchor or go into Fort St Louis Marina if you prefer. I really like the marina there and have spent a lot of time in the past. The anchorage is excellent. I'd then head around to St Barts if your crew will accept a few bumpy hours. Love St Barts. Out of season the marina is good value. Not sure about January though. Anchorage may be very busy at that time of year as well. Great bay anchorage and mooring just round the corner from Gustavia in Anse Colombier. On the way back Ile Fourchue is a pleasant stop. I've also stopped at Tintamarre which is a great day stop. Not sure about overnight.

I'm afraid I've probably outlined a too ambitious itinerary for you as we always have longer trips (and used to own a catamaran based out of the BVI) but hopefully you can get some more answers from others.