Not Ideal but easily do-able if you are experienced. Clear out at Rodney or Marigot Bay (I presume your charter is starting at one of those). First day down to the Pitons if you have time. Overnight there, up early for departure at first light aiming for Blue Lagoon St Vincent to clear in. If things go well and time allows you can carry on to Bequia instead of Blue Lagoon. After that just take your time and enjoy SVG.

Of course if you are happy doing an overnight you can just head straight out from your starting location and head to Bequia. All the nicest places are Bequia and further south (in my opinion) so you might as well get there asap.

Should say I went up and down the island chain from BVI to Grenada many times and lived aboard in the Caribbean for a couple of years. It was a few years ago though.