Coach storage up north?

[folivier]

Just getting info right now. We have the house for sale and depending on when it sells determines when we head to Alaska (either this summer or next summer). What Cindy and I were thinking about is maybe find a place up near the route (Bismarck, ND to Saskatchewan) to store the coach over the winter and what the costs would be. We're thinking maybe this summer to spend time roaming towards that area then store it, next year pick it up and head to Alaska from there. Or reverse it and store it on the way back.
Being fortunate enough to keep the coach parked at the house I've never had to store it so I'm assuming I would want a covered place with electricity to keep the batteries charged. Is heated storage worth the extra costs?
Do campgrounds up there offer storage?
I'd appreciate any info to point us in the right direction.
Thanks.