"Andrew Sarangan" writes:

I will be flying through the Toronto airspace from the southwest,
landing at Buttonville (CYKZ). It would most likely be IFR. I
realize I have to detour around Pearson (CYYZ) to the north or
south. [...]

Unless you specifically file a roundabout way such as YKF YMS KZ,
Toronto Terminal will just vector you when you get within 25 nm. If
you want to follow the lakeshore east, they'll be happy to let you.

- FChE