Okay here is my two cents on these two places.
-Very Cold and Windy
-Icy Conditions, we are talking bullet proof
-Not much pitch
-Dollar goes further
-Great après ski
-Hot ass French Canadian Bartenders at the Caribou, where they encourage you to dance on the bar
-Too commercialized hence the nickname K-Mart
-Can be too big for its' own good
-High prices overall
-Two words...Outer Limits
-Great fun on the Access Road, I would recommend the Pickle Barrel or the Wobbly Barn
I would say if you are going to make the trip, go Killington, tougher hill with great off hill activities. As far as flying in to Killington, you have four choices. First is Hartford, CT (Bradley Airport) then you have about a two-hour drive up to Killington. Next is Albany, NY then it is about an hour and change over to Killington. Next is Manchester, NH then it is about an hour and a half or so to the hill. Last is you can fly into Rutland, VT, but it might be a little difficult to get a flight into there, but if you can you are minutes from the hill.
If you are looking for a cheap place to stay, when you are looking online look for hotels in Rutland, you are a few miles from the hill but it will save you some cash that you would spend staying on the Killington Access Road.
Tremblant, you fly into Montreal then it is about an hour and a half or so north to the hill. I am not too sure of a cheap place to stay up there, but remember our dollar goes a little further up there.
I hope this helps. Enjoy the east coast, the breeder of better skiers