In a previous article, "wan2fly99" said:
Does anybody know where I can get preferred IFR routes when
coming back from the USA, say from Teteboro to Oshawa?

No flight plan survives contact with Toronto Terminal.

When I'm flying Oshawa to Rochester (which obviously goes deeper into
Toronto Terminal's airspace than you do), I just file what I want and
prepare myself to be given something entirely different - even if I file
the route I got last time.

--
Paul Tomblin http://xcski.com/blogs/pt/
"Legacy (adj): an uncomplimentary computer-industry epithet that
means 'it works'." -- Anthony DeBoer