I took a 12 night one way explorer cruise from St. Lucia to St. Maarten, threading through the beautiful and underdeveloped Leeward Islands. We visited 9 countries, and 12 islands on this outstanding, hard to find itinerary. We had 21 on board (capacity is 24), a mix of singles, married but traveling single, couples and one mother/ son pair.
This is a social cruise, you are in close quarters with everyone one, as the cabin are small (but very adequate), and you will not spend much time in them except to sleep. There are steep stairs/ladders to get up and down decks, be sure you are comfortable with that.
I understand the old barefoot windjammer cruises were serious party boats, but the new line has mellowed, and there is a good time atmosphere, 5 pm rum punch and snack hours, free flowing wine and beer, but I gather the partying is more subdued that prior years. Fine with me.
A standard cabin on the lower floor, Midships, so it was very stable. A fair amount of generator noise. Double bed below, single bed above. would be tough to sleep two adults in the lower bed because the top bunk is low.