This is outside my scope of knowledge. You can call CIC and ask but I am not sure they would even know. As a PR, you are certainly meeting your residency obligations if you live in Canada but drive to the US every day for work.
As for taxes, I believe if you are living in Canada, you need to file taxes in Canada but since it's US income, you also need to file taxes in the US. Canada and the US have a tax treaty so you should not get double taxed but you might want to have somebody else do your taxes for you.
As for the H1B visa, I am not familiar with if there is any requirement on the H1B visa to actually live in the US.
As for easy border crossings, you may want to get a Nexus card, see
http://www.cbsa-asfc.gc.ca/prog/nexus/menu-eng.html