You may wish to break up the run from Pitons and spend the night in Blue Lagoon on the southern end of SVG. There is customs clearance there as well as at least 2 restaurants. From there to Bequia is about 2 hours and have plenty of time to visit the turtle sanctuary and the fort.

I have seen the notice on PSV from Doyle Guides- not sure what this means. They give an an email to write to and a phone, In the past we have been able to go ashore but only to Goatie's with no problem. The rest of the resort has been off limits. That aside it is a great anchorage and an easy dinghy ride to Mopion and Punaise.

As for Mustique, we have only been there once. it is very nice, but a bit upscale for our tastes, YMMV. Personally I would not bother and use the time to spend an extra day in the Cays or at Salt Whistle.

If you have never been to this area, where there are moorings there are normally no pennants on them. As always, it is a good idea to dive and check it out as some of them are of questionable provenance. There will most always be a local in a dinghy nearby to help with your lines. If you toss them EC$10 and a beer for their help they will be at your disposal. If you order bread/ice, etc. from them, negotiate the price in advance and be sure if you are talking about USD or EC as they will accept both. Also, in many places the dinghy docks are a bit of an adventure - look before you grab something or jump out.