We are Canadians and have had Verizon for the past 7 years using their US, Canada, Mexico plan and have unlimited Text & Talk. Have unlimited data while in the US. In Canada, it cost $ 25.00 for 250 mb.
We have excellent coverage throughout our travels in Ontario and Manitoba as they use Telus, Bell and Rogers for area coverages.
Therefore, I think the best bet is to stick with Verizon for everything except data and get the Verizon Satellite stick. It works everywhere ( according to friends that have one ) and cost them about $65.00 per month. Not sure how much data that buys, but you could find out from Verizon.