Cycling through Toronto with a distant destination in mind is going to be s-l-o-w-w going whether you take city streets (many many many stoplights) or the Waterfront Trail, such as it is (much meandering, conflicts with toddlers, headphone-wearing rollerbladers, dogs barely controlled on those infernal adjustable leashes, etc.)

A nice alternative is to take the hourly commuter train along the Lakeshore Corridor through the most congested part of the Greater Toronto Area. You can get on as far east as Oshawa and get off as far west as Aldershot, a lot of stops but you don't have to change trains (usually) when you pass through Toronto Union downtown. You can take your bike on any train except those that are sure to be crammed with commuters: the rush hour trains that arrive at Union between 06h30 and 09h30 and those that depart Union between 15h30 and 18h30. You also can't take your bike through the main Union Station concourse during those hours, again because of the tides of commuters. Conveniently, there is a train leaving Union for the west at 18h35 if you were spending the day downtown and wanted to get out of Dodge for the night. (That train actually goes as far as Hamilton, although that's getting you rather off the path if you're heading for K-W.) The answer to a FAQ is yes, you can take your bike on a train during those embargo hours as long as you are going counter to the influx of commuters. So if you were staying overnight in Toronto and wanted to get an early start you could get on at any station west of Union (e.g. Exhibition which is only a few minutes by bike from Union) at any hour until 15h30. Just be aware that the occasional off-peak train might be really crowded at the finish of special events downtown and have no room for your bike -- for the summer daytime touring cyclist these would mostly be Toronto BlueJay baseball games and the two-week Canadian National Exhibition (late afternoons in August.) Edit: Oh, and the Caribana festival first weekend in August.

Check www.gotransit.com for details. Remember, only the Lakeshore West and the Lakeshore East lines have (hourly) train service during weekends and non-rush-hour weekdays. But all the GO buses that serve other routes have bike racks for a couple of bikes that seem to be rarely used.

If you get off at Aldershot, I suggest you avoid riding up Waterdown Road, the obvious route away from the station. It is going to be widened soon and the two-lane pavement has been allowed to deteriorate badly. It is a fairly steep climb, there is no shoulder, and traffic has increased a lot since the interchange with the freeway adjacent to the rail line was expanded. (The falsely reassuring bike lane disappears immediately past the stoplights controlling the interchange!) Snake Rd. or King Rd. are much better choices, still steep though.