Driving a Canadian car in the US for 6 months

Hi people! Driving a car in the US is a common topic, I know, but I couldn't find information about how long you can do it or what kind of permits do you need. For example, is there such thing as "temporal importation" or something like that???

I'm from Argentina, I'm plannig this long trip to north America. First I will go to Canada for 6 months and then I will be moving to the US, but before come back to Argentina I will need to visit Canada again at least for a few days. So I thought that I could buy a car in Canada, drive to the US and then come back (I will have canadian driver license). This sounds good because I don't like to fly and the cities I have to visit are not too far from the border.

Here is the question: can I drive a canadian car in the US for 6 months without any kind of importation process and with a Canadian driver license?

If the answer is no, can I drive to the US, NOT use the car while I'm in there, but use it at the end of the trip to drive back to Canada? This is an alternative, use the car just to commute.

Any experience?

Thanks guys, I'll really appreciate your help.
JD

Oh, I forgot. Can I get US insurance for a canadian car?