To advertise for a house or apartment: The Toronto Star, 1 Yonge St., Toronto, Ont. M5E 1E6. Phone (416) 368-3611.

* Furnished apartments (by week or month): Promenade Apartments, 1 Oriole Rd., Toronto, Ont. M4V 2E6. Phone (416) 960-1167.

* Metropolitan Bed and Breakfast (Toronto), c/o Elinor Bolton, 12 Danzig St., West Hill, Ont. M1E 2K8. Phone (416) 282-2280 or (416) 282-8855. (Brochure available for $2.)

Other accommodations listings and literature available from the Canadian Embassy Office of Tourism, 1771 N St. NW, Washington, D.C. 20036. Phone (202) 223-2855.

In Toronto, contact the Tourist Bureau of Metro Toronto, Toronto Eaton Centre, 220 Yonge St., Box 510, Suite 110, Toronto, Ont. M5B 2H1. Phone their "Infoline" at (416) 979-3143 for accommodations, information on shopping, special events, or virtually anything else you need to know.

To reach Toronto:

By car: Drive to Niagara Falls, N.Y., cross the border at the Rainbow Bridge (or any other bridge) into Niagara Falls, Ont. Go east onto the Queen Elizabeth Way. Toronto is straight ahead 84 miles along the lakeshore, or 134 kilometers as the Canadian signs will now say. Speed limit on highways is 100 km or just over 60 mph. Fasten seatbelts; it's the law in Canada.

Air: U.S. Air has four direct flights between Washington and Toronto every day except Saturday when there are three flights. Flying time is two hours and you get to see Niagara Falls from the air. Round-trip fares: $272.50 per adult, $204.38 per child. Ask for the Super Saver fare and if you can comply with restrictions, you can fly for $150.42 per adult, $123.17 per child.

Bus: Cheapest of all is a 10-day excursion rate offered by Greyhound. A through bus leaves Washington each evening at 7 and arrives in downtown Toronto the next morning at 8:20. Cost: $110.85 per adult, half price for kids 5-11, and free for under 5 (applies to one child per adult only). Connections can be made from Springfield, Va. Regular non-excursion rates are $45 more with the same deal for kids.

Currency: Most shops in Canada will give you a fair deal on exchange but you will usually get the highest rate at a Canadian bank.

A metric conversion table or slide gadget is handy.