The Backroads Mapbooks Island volume should be your basic resource, not only for roads, but also for rec-sites, lakes and trails. I've also bought backroads guide books, kayaking guides and hiking guides, many of them in the Ferry bookstores.
For fast access to Campbell River I use the Tsawwassen-Duke Pt ferry, and the inland freeway. Alternatives are old coast road through resort towns, and the Sunshine Coast (with good kayaking options at Sechelt and Powell River).
In Campbell River I use Elk Falls PP as a base. From there I've spent time on Quadra Island, and time out west Stillicomb PP. There is also a collection of canoe trails and campgrounds near Campbell River (see the mapbook and local forestry resources).
North of CR, the first PP is Schoen Lake, which is a ways down a gravel road. I've driven there, but not camped. Until it returns to the coast, the highway is mostly passing through logging territory. Many years ago I took a small sail boat to Kyuquot Sound, and spent 5 days sailing and camping. That's a gravel side trip.
On one trip north we spent a night a Telegraph Cove, having made a reservation over the phone in Campbell River earlier in the day. It was a lot more crowded than provincial parks.
Malcolm Island is an interesting place, quiet and quaint. There's a community campground on the NW shore, and various locally maintained trails. Alert Bay gets more tourist traffic (even cruise ships).
10 years ago we drove out to Cape Scott (50 miles of gravel?). The hike from parking to the nearest campsite on San Joseph bay is 3 miles. It might be possible to park at a rec-site or private lot before the PP parking, and kayak down the river.
