Questions about Verizon service in Canada

My wife is flying to Calgary next week for a wedding (which is 2 hours outside of Calgary), and we're on a Verizon pre-paid plan, unlimited text and talk with set data. I've tried researching it online and can't find anything definitive. We're resigned to her using we-chat from the hotel on wifi as our only real way of communicating, and we assume she'll be roaming the entire time she's there. Assumptions correct? Unlimited talk won't make a differnce out of the country, right? She'll probably be too busy to pick up the phone during the day to chat anyways, but wanted to make sure if she'd even be able to make a phone call, and if so, how much out the butt will we be charged.

Hopefully that's enough info to go on. I never travel outside of the country, so sorry if it's a dumb question.

TIA