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.