O'Connor->St. Clair->Kingston is also a decent route.. you can get to O'Connor from Broadview/Paper off Danforth, or from Pottery Rd. if you're on the Don. Any of these eastbound trips can get a bit hairy during the evening rush. Note if you take Danforth->Kingston that the merge puts you in the centre lane of 60-70 kph traffic.

For bonus fun / a scenic route if you're riding geared (& not in a hurry), bomb down Guildwood from Kingston E. of Markham, and climb back up Morningside.