Sneaking across Lake Superior undetected

All:

Can a 172 flying at 200 feet above water across Lake Superior get through
undetected by radar or AWACS? Are there holes in radar coverage?

I ask cuz I'm a mystery novelist at work on a new whodunit and wonder what
goes on when a small plane flies from Canada to the United States over a
Great Lake. I presume the small plane has to land at an official port of
entry so Customs can go over it looking for bad stuff.

Also, when a plane crosses the border does it have to be in radio contact
with ATC? (Being deaf, I'm a NORDO pilot so don't know anything about that
stuff.)

Thanks to all.

Henry