That's so funny to hear, because to us of course the accents you mentioned are soooo different. We all call it "English," but there must be 100 varieties of it.
You mention PEI, I can say that the accents in nearby Newfoundland sound altogether like Scottish to me. In fact, that island's closer to Scotland than it is to Denver.
I was on a boat to see the Orcas off the Washington Coast and in the end, I had to ask the lovely couple that I was in conversation with, just where they were from, they were Newfies, I had never heard an accent anything like it ! A touch of North American, with scouse, Irish and Scottish brogue thrown in, they had me beat, I can tell you, but now I know !
I can generally tell New Yorkers and Texans, but Canadians, I just can't, I find it really hard, as it would appear they do too! My son was speaking in a shop on Vancouver Island, and the lady called the family out to listen to him speak , apparently, sounding just like Prince Harry
I made a great faux pas in Malaysia a few years ago, was asking a couple of guys from down under about good curry house where we located. They duly told me and got onto their mopeds and bade me farewell, I said that they were emulating Kevin Swantz , they said "who is that?" an Aussie Superbike racer said I, "Aussie ? " they said, "we are Kiwis ! That's the trouble with you scots, you are all the same !"
A brilliant retort and fired with a dead pan expresion and instantly, I nearly dropped my Tiger beer laughing !
The moral of my story is, I no longer guess accents !