Ontario

When the wind and waves were moderately high, my family and I were stuck on small Thibodeau Island. Our boat was too small to ride comfortably and safely through the whitecaps. We loved that feeling of isolation. And we found that by evening or the next day the wind would die down.

Somehow there's something romantic about being marooned on an island, particularly if it is temporary, if there is no vital reason to be anywhere else , and if the vistas are as beautiful as they are in this area of Thirty Thousand Islands in Lake Huron.

Another calming thought was that the rental ''meter'' was ticking along at only a slow pace. With the Canadian dollar costing only about 80 American cents, my US dollars were stretching decidedly further. This comfortable cottage on the rocky shore, with three bedrooms and another separate bedroom in a guesthouse up the hill, was renting for a bit more than $40 a night.

In fact, Canada can be a vacation bargain these days. We had learned of our cottage from a friend's recommendation. But Ontario has an excellent travel information system in the United States to help prospective tourists. You call 1 -800-828-8585 from any state except Hawaii and Alaska (or 1-800-462-8404 from New York State) and those answering will send you a Traveler's Encyclopedia, a booklet of Accommodations, an Official Road Map, and probably other pamphlets if you have something specific in mind.

Of course, picking a cottage by telephone anywhere is taking a pig in a poke - it's risky. But the booklet does at least list the prices, facilities, and services offered by each accommodation. These prices are relatively inexpensive compared with those in New England or New York. And certainly this Georgian Bay area is delightful, with its many islands and channels that are fun for boating or fishing. In midsummer the water is decidedly cool, but not frigid.

What we did on this vacation was first drive 10 hours from Boston to Niagara Falls on the Canadian side. With some 12 million tourists visiting each year, the downtown falls area has developed into a sort of high-class Coney Island. The Niagara Parks Commission maintains a beautiful strip of parkland, including a greenhouse and floral clock, along the Ontario side of the Niagara River and the falls. Behind this strip, all sorts of entertainment for visitors has sprung up. There's a Marineland with its killer whale and dolphin shows; two towers with dining rooms on top overlooking the falls; two sizable, relatively clean, and fancy amusement parks, and more smaller ones; a giant water slide; Niagara Falls museum, a wax museum; shops galore; and many other attractions, some of which might be classified as ''tourist traps.'' To me, the carnival atmosphere takes away from the majesty of the falls themselves. Our children thought differently.

In any case, we left soon on a four-hour drive to Stratford and the famous Stratford Festival. That festival is an impressive accomplishment for a small city. This summer it runs through Oct. 22, and includes Shakespeare's ''Macbeth, '' ''As You Like It,'' ''Richard II,'' ''Love's Labour Lost,'' and ''Much Ado About Nothing.'' Also playing will be Moliere's ''Tartuffe,'' Gilbert and Sullivan's ''The Gondoliers'' and ''The Mikado,'' William Wycherley's ''The Country Wife,'' and Arthur Miller's ''Death of a Salesman.'' There are also four 'virtuoso performances'' by solo actors; celebrity lectures; and seven concerts by name performers or bands.

Tickets run from $6.50 to $25 for the Festival Theatre plays. A booklet on the festival can be obtained by writing Publicity Department, Festival Theatre, Stratford, Ontario, Canada N5A6V2, or calling (519) 271-4040.

Accommodations in various hotels and motels is quite reasonable. We stayed in a ''bed and breakfast'' home (River Garden House, (519) 271-1403) overlooking the Avon River. It was an old home, charming, clean, and, in regard to the breakfast served by the mistress of the house, delicious. It cost $20 for a single room, $25 for a double. Names of further such accommodation can be had by calling Stratford Area Bed & Breakfast, (519) 271-5140, or writing to 38 Albert Street, Stratford, Ontario N5A3K3.

After the festival we drove a half day through the green Ontario countryside, past the outskirts of Toronto, and north on Route 400 to Honey Harbor. The half-hour run to Thibodeau Island on the water taxi, loaded with all our luggage , cost about $20 each way.

The cottage lived up to our expectations. The glass-walled living room looked over an open space of water to numerous other islands, the closest perhaps three-quarters of a mile away. It had a fireplace that took the chill away in the evenings. The kitchen and bathroom facilities were modern. We had the use of a somewhat battered fiber-glass canoe and an aluminum boat with a small outboard motor. The nine-acre island was shared with three other cottages, two possessing telephones. The rocky hilltop behind our house was partly covered with patches of thick moss ideal for sunbathers. The views were fabulous.

We managed to extend our stay a couple of days, giving us more time to boat through the various passages to islands, including nearby Beausoleil Island, part of Georgian Bay Islands National Park. Beausoleil has some pleasant trails for walking, as well as a good beach for swimming.

When the water taxi came to take us and our belongings to Honey Harbor, we left with reluctance. On the way home, we stopped in Toronto. It is one of the most vibrant, well-managed cities on the continent. When I lived there some 24 years ago, Hogtown (as it is nicknamed) was conservative, a bit stuffy, and dull. Now an infusion of immigrants from all over the world and the changing times have turned it into a lively, cosmopolitan city with excellent restaurants (the phone book lists restaurants under 42 kinds of ethnic cuisine), shopping facilities, museums, concert facilities, subways, and all the other accoutrements of a major, modern city.

From Toronto, we drove home to Boston via the northern side of Lake Ontario for a scenic change of pace. Our bank balance was reduced, of course, but by perhaps half as much as if we had spent the time at similar facilities on Cape Cod. Canada can be a good vacation buy these days.