We started planning our route about a year in advance, and good thing we did. Canada's national parks were all booked full by then, but we found sites available in the BC Provincial Parks, which are generally smaller and quieter and a little more off the beaten track.
As I inevitably do, I got overambitious about getting off the beaten track and planned too many long drives on logging roads to get to the really remote places (Carmanah Walbran was the most enticing). Fortunately, my much more mindful girlfriend, Heidi, suggested (subtly) that we not overextend ourselves and instead enjoy fewer places that are easier to get to. This was very lucky, because it turns out that some of these roads were really too much for our car/camper/canoe set up. I decided to drop most of the unpaved roads from this trip, but kept two, the ones to Clayoquot Arm and Schoen Lake, partly because these parks included opportunities to go remote by canoe and partly because I was curious how our new camper would handle slightly rougher roads. Spoiler: it managed wonderfully.
We had an itinerary, which was good and necessary, as some of the parks required reservations, and it can be disconcerting to pull into a campground to find no room left, or just the loudest, most exposed sites available. We decided to take the ferry from Anacortes to Sydney this time, which gave us a glimpse of the San Juan Islands, where I lived for a couple of summers a few decades ago. We also saw an Orca or two on our crossing. Sydney is a small town with tight streets, especially if you're towing a trailer. We loaded up on groceries and headed up island.
Our first stop was Cowichan River, where we spent a couple nights and got a chance to test all systems on the camper. This way if anything needed adjusting or resupplying, we could do that easily before getting further from civilization. Not that we didn't pass through Nanaimo, and Vancouver Island isn't exactly remote any more, at least not until you get up past Campbell River.