Bring American gf to Canada

Hi there,
I have been studying both the American and Canadian Immigration processes and so far...its all pretty straight forward. Mind you exhausting at the same time.

So for now I am looking to bring my American gf to Canada to live with me. I understand she wont' be able to work while here. I have a few questions and was hoping someone could help me out.

1. I have been living with her for 4.5 months in the US and if she were to move with me into Canada and live together for another 8 months or so could she apply for PR from within Canada as a common-law partner? And what kind of time-line would we be looking at? I've read Mississauga is pretty fast but Buffalo is pretty slow. Could she apply to work while the PR process is ongoing?

2. How would we go about her coming from the US into Canada with her things? A visa isn't really necessary from what I've read. Our final intention is for me and her to move to the US after we apply for a K1 from within Canada after we get engaged. This would be after a couple years or so.

Big Thanks for any help!
Cheers,
John