Are you asking about brick and mortar stores? Pretty much everything is online only, so it doesn't matter what province they are located in. I could mail a package across the country in the same amount of time it takes to mail it across the city.
Canada Post standards for Xpresspost -
Anything sent from a major city to a major city - between Vancouver and Montreal - is guaranteed 1 - 2 days delivery (not counting the send date).
All points west of vancouver and east of montreal - guaranteed 2 - 4 days delivery.
All points north of the provinces or remote communities have a separate delivery schedule.
Anything sent within a single province is next day for most communities - 2 days for more remote communities.
...gotta love the fine print!