Whistler to Wells Gray = 6 hours
Wells Gray to Jasper = 4 hours
Jasper to Banff = 4 hours
Banff to Calgary airport = 1.8 hours

I would drive straight to Jasper from Wells Gray.

You may not have thought this was the problem, but it is almost 8 hours travel time to get to Whistler from Tofino, including the ferry (2:10).

Are you perhaps flying to Tofino from Vancouver (7 hours surface time)?

I would perhaps do it this way:

Vancouver - 3 nights
Tofino 3 nights

It takes a minimum of 5 hours to travel from Vancouver to Tofino. 30 minute drive from Vancouver to Horseshoe Bay, the wait at the ferry terminal, the 90 minute ferry to Nanaimo, then the 3 hour drive west across Vancouver Island to the Pacific coast (not including stops).

This is why I recommend the following after Tofino

Vancouver 1 night
Whistler 1 night

After travelling the 5+ hours from Tofino, do you want to do the 2 hour drive to Whistler? Perhaps... but you may be too tired to want to stop off at places like Shannon Falls and Brandywine Falls along the way. If you do want 2 nights in Whistler (which is lovely in August), anticipate a long day on the road after Tofino, that's all. It will also be a long day on the road from Whistler to Well's Gray, but it's a spectacular drive.

2 nights Well's Gray
2 nights Jasper
3 nights Banff

Hello everyone that is very fine to doing the traveling from Vancouver to Calgary we can find it a bit boring but you can make it will take some refreshing things to take rest for sometime in Shannon Falls and Brandywine Falls while you are on the way!

Thanks for all your replies, is there anywhere to stop along the way from Whistler to Wells Gray, especially after the previous long journey Tofino to Whistler, which we are rethinking.
Thanks again