Staying @Marriot, which is the closest supermarket to prep for NYE dinner?
Best grocery stores are in St Jovite. Will you have a car?
On our way in, we usually stop at the Metro Mt. Tremblant which is in the former town of St. Jovite. St. Jovite has been amalgamated into the greater Mt. Tremblant, but to me it's still St. Jovite. It's got the best of selection including many ready made meals so we don't have to cook the first night there. The Marche du Village - Bonichoix in the old town of Mt. Tremblant is a much smaller grocery store, and the closest to the slopeside village. We've done our grocery shopping there a few times for a 4/5 day stay, but usually just go to the store when we just need a couple of things. But as bogwoppit suggests, you really need a car to get around the area. Google directions.
I took the bus from Residence Inn yesterday to the Metro in St Jovite. Bus ran to time, very easy journey and the store had all the fresh items I required for cooking for us, including turkey for Christmas Day. Our suite at the Residence Inn is very lacking in cooking equipment, one tiny baking sheet, a frying panand saucepan so you might want to consider buying some foil trays to cook in.
I am a bit late for this post since we are on the 24th but anyways...
So there are 3 supermarkets side by side on the outskirt of Saint-Jovite near road 117. Of those 3 it seems that IGA is the best so if you have a car that is an option. If not then there is a bus stop close by but it is really in the middle of nowhere wile the Métro is right in the middle of the town and the bus stop has a shelter and is right there by the side of the church.
The great thing about being in Saint-Jovite proper is that you can also have a look at Bourassa which is a very interesting kind of cash and carry geared to restaurateurs but also to the general public. Their selection of local cheeses is amazing and nowadays they even make their own Montréal style bagels everyday. Do not confuse them as they also carry the original Saint-Viateur but those might be a bit old while their own are fresh for the morning and so do not need to be toasted. Saint Jovite proper has a SAQ (provincial liquor store) that has a way better selection than the one in the resort. It also has a Dollarama which will be the place to goif you want to stock on aluminium trays and molds but also very cheap pans that will be good for 2 or 3 times.