If you want to be able to live in Canada permanently, you need to apply for permanent residency, see
http://www.cic.gc.ca/english/immigrate/index.aspYou can live in Canada for up to 6 months at a time as a tourist. If you get yourself a Nexus card, you will be able to cross the border easier without too many questions asked.
I am not sure about the taxes, ask an accountant but I believe if you are PR living in Canada and working in the US, you should file taxes in both countries. They have a tax treaty so it's not like you are paying double. If you are just staying in Canada as a tourist, then of course you only pay tax in the US.