I have done it with NautiNymph and used their captain. They picked us up at Sapphire early in the morning and we went directly to Virgin Gorda. Our capt dropped us off in the water at the baths (we swam in using fins). He took our passports to customs for us (not sure how this works, and things may be tighter now). He told us where he would be when we were ready to return and we swam back out when ready. He then took us to Foxys for lunch. We treated him to lunch and he sat and ate with us. Then he took us, via boat, to White Bay where we spent the rest of the day. We headed back to STT where we gassed up and concluded the trip.

We did rent the largest boat they had (I think 29 ft Fountain) and the most powerful twin engines because they would get us to out destinations faster.

Also, factor gas into your expenses...frankly, the gas was much more expensive than we expected and almost doubled the cost of the trip.