Pre-paid mobile service provider that does US to Canada and Canada to US?...

[discntnt_irny_srcsm]

12. I kind of thought we might be discussing car trouble comms

For a year+ I worked where I had to drive through areas with no coverage. I bought a CB radio.
This one: https://mid.factoryoutletstore.com/cat/35527-98437/Midland-Mobile-CB-Radios.html?cid=85369&chid=4272&gclid=Cj0KCQjwrfvsBRD7ARIsAKuDvMOyMx0PCB4_jOydHGPOtiiHgMjGdhkIFTeazTEoRLNkKEjX7HjIE9EaArvyEALw_wcB

I bought this antenna: https://www.ebay.com/c/165213312?iid=282113812833

CB works in Canada the same as the US for the most part from what I read.

Truckers and some rural sheriffs departments are probably the only folks you're likely to reach but no monthly fee at all.

Here is a link to whistleout with the coverage map at the bottom of the page centered on Tupper Lake:
https://www.whistleout.com/CellPhones/Search?minutes=300&sms=500&data=500&fullspeeddata=false&address=Tupper+Lake+NY&tab=all

The greenish areas have no coverage.

For the most part the only real universal coverage is a satellite phone:
https://satellitephonestore.com/iridium-services

From looking at coverage maps ATT and Verizon seem to have the most areas available in your part of the US. I'm not sure about Canada.

Best of luck.