Do you intend to "roam" in Canada? I'd check with your Verizon/AT&T carriers and
1) see what it will cost to use your US phones up here? I think some have add ons or plans which include use while in Canada.
I know that roaming with Canadian phones in the US can be very costly. We use prepaid AT&T and T-Mobile sim cards while in the US. Not sure about the reverse? It might be easier to get a prepaid Canadian sim card and number for the 6 weeks and add funds as required.
2) see who they have reciprocal tower coverage with? I believe AT&T uses Rogers towers in Canada, and Verizon might be Bell? Then check their coverage maps.