Vancouver Island (VI) is a very beautiful place to visit. Although an island, it is a very large land mass and you will not be able to see it all. The east coast is much more developed and the weather there is more predictable. The west coast is sparsely developed (mostly due to ruggedness and little access) and the weather is less predictable. The land between the two coast lines is very mountainous with peaks reaching 7,200 ft elevation. In addition there are a number of smaller islands, mostly off the east coast, that are developed and have unique lifestyles to each. They, unfortunately, also require an additional ferry fare to get to each one.
We just got back from a week on VI with time spent near Victoria for a family reunion and then camping at Long Beach area, on the west coast at Pacific Rim National Park.
There are numerous Provincial Parks camp grounds on VI and they are all spectacular to visit. Some are on the shoreline and some inland along rivers and lakes. I have no experience with private campgrounds on VI. VI does get very busy with tourists in the summer season and reservations are required/recommended. There is a Federal Park on the west coast, Pacific Rim, at Long Beach.
BC Parks - Province of British Columbia
The third photo in the included set was taken near Ucluelet on the west coast. There is a white dot on the water in front of the boat in the center of the photo. That was a whale spouting which we happened to spot as we were walking along the coast, before the whale watching boat showed up. We watched the whale for some time as it spouted and breached. The bottom photo was taken at Tofino.