2 weeks? ADVICE: HAVE FUN!!!
I have 23 weeks before I leave for the Grande.
Regarding the helicopter. I booked it through my TA (and my TA contacted Sandals in St Lucia and set it all up with St Lucia Helicopters, etc). . We will fly both ways by helicopter. You need a minimum of 4 people to have them land directly at the Grande. At least that's how it was when we booked. It costs about $110 US per person each way. Sound like a lot? Book a helicopter tour anywhere you go and it'll be at least that much.

Anyways.. .. . doing it this way STILL saves me over $200 per person in airfare by flying into the larger southern airport rather than the smaller northern one AND it saves me about 7 HOURS of travel time. ( 6 hours travel time total going into southern airport from here.. .. .. . 13 hours if I fly into the northern airport )
PLAN YOUR LUGGAGE if you're taking the helicopter. You get to take on the helicopter whatever your airplane carry-on is. The rest of your luggage goes on the taxi-bus and will arrive at the resort about an hour and a half AFTER you arrive. So plan on having what you will want to wear in your carry-on if you feel you'll be wanting to change clothes for dinner or something.
oh and by the way.. .. .. . HAVE FUN!