Flying over Canada VFR

You need to be talking to some ATC while you're crossing the border. It's
easiest if you get flight following the whole way. NavCanada will send
the aircraft owner a bill for $15, but will cover the aircraft for the
whole quarter, if you decide to do it again.

Not necessarily.
I fly from Columbus Ohio to Port Huron Michigan. Heading 005 degrees.
I go feet wet at Sandusky Ohio, cross between Middle Bass and Kelly's
Islands; fly west of Pelee Island and go feet dry at Leamington Ontario.
I then go feet wet again at the south shore of Lake St Claire and feet
dry at the mouth of the channel leading to Lake Huron.
If I go IFR or use flight following, I never talk to a Canadian
controller (Columbus, Mansfield, Cleveland, Detriot, Selfrige). Or, VFR,
I may not talk to anyone.
No ADIZ flight plan, not NavCanada fees.