I've purchased a number of US timeshares from various states. It's a lot easier to buy one than sell one, usually.
As a former British Columbia notary public - not REpublic - sorry, although it would be nice to be my own country - LOL - I can confirm that although some states will simply accept a document notarized by a Canadian notary or lawyer, many, I would say most, will not. There's a whole process of getting the signature confirmed by the regulatory body - the notary society or law society of the province you sign in, then getting that confirmation confirmed by the US embassy.
That's why I drive across the border to Washington State to have my signatures notarized when selling or giving away a timeshare. I've talked to LT transfers about this, there's a totally different procedure for the two timeshare's I'm currently dealing with if I was signing in Canada.
But Canadians purchasing, shouldn't be any difficulties.
As an aside, I seem to remember that when I bought a couple of Hawaii timeshares, long since resold, I had to have my signatures witnessed or notarized. I think we were actually going to Hawaii at the time and I just did it while there.