I know this is the B.C. Forum, but the best route I can think of, for that length of trip (7-10+ days), is in Alberta, near the B.C. border.
That is one drawback of the Coastal and Interior (Purcell/Selkirk/Kootenay) ranges, they offer little in the way of week-plus routes on (mostly) trails.
Jasper and Banff park have super-long remote trails, like North and South Boundary trail, but there are extended valley forested sections.
A combination of provincial and national park trails (part of the Great Divide route) can be linked as follows for a spectacular route:
Start at Kananaskis Lakes - to Aster Lake - Northover Ridge - South Kananaskis Pass - Beatty Creek to Palliser River - Palliser Pass - Spray River - Bryant Creek - Assiniboine Park (worth 2 days) - Sunshine Meadows - Bow Valley Highline trail all the way to Twin Lakes on Hwy 93.
That is a one-way route.
For a shorter exit and easy hitchhike back to your car, exit the Palliser River up to Burstall Pass, Birdwood Traverse to Smuts Pass, and exit to Spray Lakes Road.
This is a late reply (July), but I just joined ClubTread. If the sites are booked up this year, try next year and book early.
Last edited by Gstrail; 07-06-2021 at 05:01 AM.
Reason: geographical error