Yintheheck, are you in high school?  Is this a high school ski trip?

I haven't been to Whiteface but my family likes to ski and we often go in the northeast (i.e., very cold). 

First of all, you need to bring some goodies to keep in your pockets while skiing. I mean little squares of chocolate and the like.  Also, trail bars as you mentioned.  My husband likes the KIND bars because they are mostly fruit and nuts and even if they freeze--they're mostly nuts so it doesn't matter much anyway if they're frozen.  Any kind of soft bar will most likely mush up while in your pockets.  Vegan skittles are not a good choice, either.

Second, for trips like this we like to take advantage of the world of processed foods. Seriously, that is what they're here for--to help us out when we have no kitchen of our own.  Some of the restaurants at the ski lodges are surprisingly veg friendly, but most are definitely not. I have always found ski trips to be very challenging.  When it is cold the rest of the world turns to meat, meat, meat.  While you most likely will be able to score at least some plain pasta or rice, you should go prepared.  However, this is only a weekend trip, so being prepared isnt that hard.

I like to bake a package of fake chickn nuggets/cutlets and bring it with me.  You need to cook them before you bring them along.  I find if I keep them refrigerated in a cooler bag they will last at least a day.  Thsi is my favorite food to bring on plane trips because then you don't have to worry about someone with a peanut allergy asking you not to eat your sandiwch.

Two more suggestions--bring a mostly ripe avocado and a package of tofurkey slices in your small cooler bag.  Chances are you will be able to get some bread and slices of tomato wherever you are.  Add some tofurkey and avocado and you have a very substantial lunch.  The peppered tofurkey makes a tasty sandwich.  Most ski lodges have no objections to people bringing in their own lunches. You can also purchase a gatorade or some fruit from the cafeteria.

The other thing I would bring is a package or two of either a cup-a-soup bowl (Fantastic Foods makes a whole line of substantial soups) or those heat and eat Indian entrees (check the labels).  You should bring these as emergency backup only. Chances are you will be able to get through your trip without having to eat these.  But you should have a couple of these stashed as emergency backup in case things are truly desperate.

Lastly, you need to bring some oreo type cookies, some pop-tart type thing and some raisins or dates. And don't let your friends eat all of them.

Oh wait. I forgot.  If you are vegan you should definitely bring a vegan hot chocolate mix.  That is something I have never seen at the lodges, and a very nice thing to have along.