Wilderness Excursions in Canada : Non-strenuous hiking and canoeing holidays are offered in Mt. Robson Provincial Park.

Travelers over 50 who enjoy easy adventure trips can avail themselves of either one of two modestly priced packages this summer in the great mountain outdoors of Western Canada.

Both holidays are based in Mt. Robson Provincial Park, British Columbia, immediately west of Jasper National Park, Alberta.

Fifty Plus excursion participants will spend five nights in comfortable furnished cabins. Daytime activities will include walking, flat-water canoeing, a history tour to an abandoned town, and a gentle rafting trip. Areas to be explored are rich with wildlife--moose, elk, beaver and bear--and two experienced guides provide information about natural history.

The Helicamping Adventure Trip, utilizing helicopters to reach otherwise inaccessible sites, emphasizes moderate hiking. The first and last nights are spent in comfortable cabins, the other three nights in large private tents at scenic Berg Lake, to which participants are flown. Average altitude in Mt. Robson Provincial Park is 2,800 feet.

Both packages include all meals, accommodations, equipment and guides. The Fifty Plus adventure takes place June 13-19 and Aug. 28-Sept. 3. The per-person cost, based on double occupancy, is $575 U.S. The Helicamping Adventure Trip is Aug. 19-24 and costs $845 per person, double.

The nearest major airports to Mt. Robson are Calgary and Edmonton, Alberta. Driving time from either airport is four to five hours. Transportation from Edmonton is available by Greyhound Bus or VIA Rail. A parking area for RVs is also available.

For more information, write Mt. Robson Adventure Holidays, Box 687, Valemount, B.C. V0E 2Z0, Canada, or call (604) 566-4386.

Seniors taking rafting trips down the Salmon River Gorge in Idaho can bring their grandchildren for half-price through Idaho Afloat, which has offered rafting trips for mature travelers for 10 years.

Salmon River Gorge campsites are on white-sand beaches, with spectacular scenery and ample opportunities to observe wildlife that may include elk, bear, deer, cougar and eagles. Guests travel on a stable 22-foot cargo raft that carriers all equipment and luggage.

Overnight camps feature large tents for sleeping, plus dining tables and portable sanitation facilities. Food service includes evening hors d’oeuvres with wine, lunches and dinners, plus full country-style breakfasts that include fresh fruit and freshly baked bran muffins.

The four-day Salmon River trips for grandparents and grandchildren depart from Lewiston, Ida., July 7, 14, 21 or 28. The adult price is $800; children are $400. Idaho Afloat advises that grandchildren may be up to 21 years of age, if the young ones are not related to the grandparents--perhaps the child of a neighbor--they still qualify.

Travelers must make their own transportation arrangements to get to and from Lewiston.

For complete details and a brochure on other trips, contact Idaho Afloat, P.O. Box 542, Grangeville, Ida. 83530, (208) 983-2414.