That's a nice loop - I've done it on a bike in 5 days, so you will have lots of time to tour and sightsee along the way. Some things to consider -

The Sunshine Coast (between Powell River and Gibsons) is quiet and scenic. Lots of natural beauty, a very popular local getaway from the city, but not a lot in the way of typical tourist attractions. Plan on outdoor pursuits like hiking or kayaking. Get familiar with BC Parks along there. I'm not familiar with Powell River, but Sechelt and Gibsons are both nice communities.

Consider time on the Gulf Islands - you can ferry from Swartz Bay to Fulford Harbour on Saltspring then get off the island at the north end at Vesuvius to continue your trip north (or the other way around if you are going to end your trip in Victoria). I'm also fond of Denman and Hornby Island south of Courtney.

Do your research for the bit between Victoria and Courtenay - lots to see and do through there, so take your time. Chemainus, Duncan, Nanaimo, Parksvillle are all worth a visit.

Perhaps I should add that my five day bike trip only went as far as the Nanaimo-Horseshoe Bay ferry crossing. It didn't include the south island, which you would on your trip.

That does sound like a nice loop. I have a personal aversion to the ferries (despite the fact that they are a beautiful way to get places and see scenery) because I hate waiting. Early October is not likely to be too busy on the ferries, but Canadian Thankgiving weekend is October 11th to 13th, so that would be busier.

An alternative would be Vancouver to the Interior wine/lakes area and coastal mountains going up through Whistler and Pemberton, down to Kelowna and the wine region and back through Princeton and Manning Park. This is easily doable in 6 days without rushing and you would see some beautiful and diverse places and have a great drive. The Okanagan wine festival is on in early October: http://www.owfs.com. If wine is not your thing there are lots of other thing to do along that route.

If you are thinking about that route, there are also many great places to stay.

Yes, the Okanagan would be another lovely itinerary. You could go via Whistler, out to Lillooet, then over to Kelowna, down through Summerland, Penticton, Oliver, Oosoyous, back along highway 3 though Keremeos, Princeton, Manning Park and Hope.

But we don't want to confuse you! There's so much to do and see here, so you need to pick your itinerary and stick to your guns! :>