Free trip to the Caribbean?

These frequent flier miles can be a pain. I'm currently working on trying to cash in my frequently flier miles to go to Trinidad for my cousin's wedding this April. I've seen tickets for $550, plus taxes. But I have have miles on United, and I can top off my Delta (and cash 'em out on Continental.) However, I can't get a flight home. These damn airline alliances!

(Y'all know that I don't mean that. How else did I get to Australia on a $101.12 ticket but on my Mileage Plus Awards on Star Alliance carriers?)

However the issues are: if I travel to Port of Spain (POS) on BWIA West Indies Airways redeeming my United miles, I can only travel on UA or BWI flights. Or I can take the StarAlliance to POS, the only reasonible carrier to take from North America to Trinidad is Air Canada.

Traveling to POS is fine, but coming home there are no United flights available within the US from my BWIA flight. (Sure there are US airways flights, but I can't get them because of the redemption rules that BWIA has with its partner carriers.) There just aren't many Air Canada flights for YYZ (Toronto) from POS, and they are all booked for three days out. (Oh, and the flight back is not direct, there's a lay over in Caracas.)

Well, tomorrow is another day.