oh boy, Inside passage is it's own trip! Northern Vancouver Island, well, You could spend a nice week over there if you were done on the sunshine coast in the two weeks.
There are a number of campgrounds on the North Island. Once the long weekend is done, folks will be heading home and it will get quiet up there. A nice Forest rec site to use as a central base is the one at Marble River. It's accessible by pavement, so no worries about gravel. Telegraph Cove is cool.
Alert Bay is worth a visit. Especially the U'mista Cultural Center. http://www.umista.org/
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