If you don't want to make the travel an all day affair, take a look at JetBlue out of JFK or BOS. There are typically red eye flights from both of those airports to san Juan. You could then take an early morning flight the next morning and be on Tortola early in the morning. I imagine you could get a direct flight from Toronto to JFK our BOS. Maybe even end of day, so you aren't doing much travel during vacation time.

We've done this out of Boston many times. Work a full day Friday and head to the airport that evening for a midnight flight. Then a 7am flight from san Juan. So we try to sleep on the plane and then have breakfast in the airport before the morning flight. We've found the cost of this for us to be close enough to flying in to St Thomas especially considering we gain a whole day as flying to St Thomas we'd get in end of day.