I was afraid this was gonna be the case! I finally found the various JFK and Toronto flights after looking on OAG instead of just searching on the usual travel sites. These flights don't show up on the Travelocities et al at all, I'm guessing because Caribbean Air and the others don't make their inventories available to them.

Looks like a 10 day chunk is going to be the minimum time to allot. Darn. Guess there's a reason we keep ending up in the USVI or BVI. Kinda hard to compete with that convenience.