You're going to have to create a new thread for this one if you want to go any farther with it. Having said that, I'll go ahead and give you some input.
First off, people are going to give you a lot of grief about the fact that there's already a map of Canada and one of the USA. I like that you've included Mexico, and Alaska, but there are definitely going to be haters. So the first thing you're going to have to do is come up with a design that is different enough from the other two that you are justified in making it.
First off, I would find a different map to use as your design base. See if you can find one that looks as it would on a globe. This will give you more room to play with the Mexico region, and Alaska won't be 1/6 the size of the entire board.
Speaking of Alaska, remember, it doesn't have to be a realistically political map. You can divide it up if you see fit, and you can certainly group the United States in ways that may not be entirely faithful to what we Americans learn in geography. I really do like the idea of a map that has more than 42 countries (as Marvaddin said, one with 60 means you never have to deal with neutral), but when it comes time to put those little numbers down on the board, alongside the name of the country, you're going to need a little more room.
That's it for now, if I type any more I'm gonna get carpel-tunnel. Sorry if that was a little long-winded, but I feel it's all more or less relevant. Good luck with your map, I'll be interested to see what direction you decide to take it in.