Must visit Factory Outlet is the one outside NYC, about an hour plus - in Apple Valley (could be Central Valley, I forgot). Woodbury Premium Outlet - MUST visit if you like shopping, in my opinion. When I was living in Boston, used to drive 3 1/2 - 4 hours just to get there. Also Filene's Basement in NYC. Some pretty good bargain have been had.
What sort of accommodation etc are you looking for?
I'm happy to help as much as I can. PM me if need to. Am still a Singaporean

but have lived in the USA for more than 10 years.
March is cold. In the past, we've had some pretty heavy snow days in March.
For comfy reasonable airfare, I would say Virgin American is my first choice. I commute between Boston, NY and CA and fly Virgin whenever possible. And one of the tricks, well, not tricks, but one way for an upgrade and a cheaper than the actual published price on Virgin America's website is to ask at the counter if there are either bulkhead seats or First Class seats available for an upgrade.
To me, it's worth the money because you have 1 free check-in when flying their bulkhead and 2 free check-ins (bags) when flying First.
Hope this is of some help.
Good Luck
