I can say that I live in the area furthest to the north that Toronto center covers, which is just north of Muskoka, on the edge of freq 127.0 to as far north as, I believe up to the Moosonee CYMO 270 degree radial, which is linked with our Timmins freq 128.3 and 133.72, then it's unctontrolled airspace, or pilots will switch to Winnipeg Ctr CZYG. It's generally a 10 hour vehicle trip without stops. I know that between the Hearst and North Bay radar sites there is about 130 some nautical miles. That's the best way I can answer you.