I don't know the answer since the aircraft is not yet in service and I could not find any performance charts. With the temps in the BVI I would guess you would need at least 5000 feet for Miami and 5500 for NYC. Published ranges are almost useless in looking at a city pair because of the varibles.
Life rafts for instance add a lot of weight. You can get by without them but then have route restrictions. Obstacles in the departure corridor have a big effect on takeoff weight and weather at the destination can require additional fuel.
One option would be to depart EIS and go to SJU for a fuel only stop. If you took on only fuel and did not go to a gate you could make a very quick turn. 15 minutes would be possible if the truck is waiting. From there you could make most Eastern US cities. The fuel stop however adds costs.
Last I heard the plans to extend the runway are still a go. I suspect Trellis Bay will be the casulity of the plan. I know several locals I spoke with are in favor of the extension. I was surprised to find they are very aware of Cuba and its potential to draw tourists from the US. They feel it's important to make it easier to get to the BVI.
G