Toronto to Niagara Falls: 125km
Toronto to Windsor: 380km
Toronto to Ottawa: 450km
Toronto to Thunder Bay: 1470km
As a general rule, Greyhound Canada covers southwestern Ontario and Ottawa, from Toronto; Ontario Northland takes care of Northern Ontario; and Megabus offers dirt-cheap services from Toronto along the eastern corridor to Montréal, as well as to Niagara Falls and over the border to Buffalo, NY. With the latter, booking tickets well in advance can get huge discounts. If one carrier doesn't service the route you need, check the others.
Go Transit (www.gotransit.com) is a bus service that takes you to places near Toronto, such as Hamilton and London. Parkbus offers limited seasonal departures to Ontario's best national and provincial parks. Check the website for details.
Car & Motorcycle
Outside Toronto, Ontario's roads are in good shape and offer a pleasant driving experience (once you're off busy Hwy 401). When driving in Ontario, you can turn right on a red light after first having made a full stop. It's illegal to text or talk on a mobile device while driving. Try to observe speed limits in the north, despite the temptation to gun it down those empty roads, as fines exceed $100 even for minor infractions.
Car rental is practically essential if you want to enjoy the province, but not for exploring Toronto – driving and parking downtown is painful enough for residents who know their way around, but could really mess up your day as a visitor. Instead, use the TTC (Toronto Tranist Commission) in the city and pick up your rental on the day you're leaving: there is no shortage of car-rental companies. Rental is cheaper in Toronto than anywhere else, including Ottawa.
The two main highways are the Trans-Canada (Hwy 17) from Ottawa northwest to the Manitoba border (just west of Kenora); and the 401, which runs southwest from the Ontario–Québec border to Windsor and the US border with Detroit.