Timex:
I heard from a former CF-100 driver that during the early 60's they did it by flying at low level via Hudson Strait, Hudson Bay, James Bay and on southward over Ontario and onwards into the US. They then climbed to a sane altitude and announced themselves much to the consternation of all else concerned.
Looking at the configuration of the Dew, Mid-Canada and Pinetree Lines and using some inspired terrain masking it may well have been possible.
Interceptors close to the track would have been available from CFS Val Dor ( CYVO ) North Bay (CYYB ) and Ottawa (CYOW )
Whether this is true or not I do not know - but it makes a good story!
Some nice surfing can be found at:
Pinetree Line web:
http://www.pinetreeline.org/
DEW Line web
www.lswilson.ca/dewline.htm
Mid Canada Line web
http://www.lswilson.ca/mcl.htm