AT&T cellphone coverage In Nova Scotia and currency question

We are looking into taking a car ferry ride over from Maine and doing a hotel for a couple of days. That way we can get around to see the sights while leaving the RV in Bangor.
I can go off the grid for a couple of days comfortably.
I worked in (radio) communications for 40 years and seem to have developed an aversion to being out of contact for extended periods.
Bob