Eating vegan in NFLD can be tough or it can be easy, depending on where you go. I'm not familiar with stores in that area, but I had a lot of luck with one of the grocery chains in Gander (I forget which one, a variation of Superstore I believe). There was soy milk, and lots of non-dairy options, etc They had a well stocked 'natural/organic food section'. If you're able to cook for yourself, it should be no problem at all.
We were actually pleasantly surprised on our visit to Gros Morne when we finally found Java Jacks in Rocky Harbour. They sold a take-out "vegan wrap" (I nearly fell over when I saw the word "vegan" after a couple of days of having a hard time finding vegan food) And they also had an item not on the menu called the vegan dream or something like that, and it was a stuffed pepper and sooo good!
So yes, it is possible, but a bit trickier in smaller towns (those grocery stores didn't carry much in the way of vegan-friendly non-dairy type items).