Goats on the Roof market in Coombs on the way to Tofino/Cathedral Grove. If you miss out on this you're missing out on one of the best things that island has to offer.
Also this is right by Parksville and Qualicum and the beach in particular in Parksville is fantastic. There is a provincial park called Rathtrevor also in that area that you don't have a hope of getting into now for camping, but you should go as a day trip if you can because at low tide the water is a solid kilometer out and the sand flats are full of amazing things particularly at low tide (gooey duck clams that squirt at you, sand dollars, etc.) Do a whale watching tour either out of Victoria or Tofino. If you're adventurous, do a zodiac whale watching tour. It's a blast!! Obviously if you go to Tofino/Ucluelet be sure to spend at least a half day at Long Beach and/or Comber's beach. The hot springs boat ride that Tyler mention, is also worth it. You get this hot spring right at the waters edge and it spills into tidepool into tidepool. The closer you get to the ocean, the cooler the water. It's brilliantly hot at the top and brilliantly cold at the bottom. Plus there is about a kilometre's walk on a boardwalk through the forest from where the boat drops you off. So pretty.
Also around Coombs/Parksville/Qualicum there is Englishman River Falls, another provincial park, don't have to camp but it's worth seeing. If you're adventurous, go for a swim there. If you're VERY adventurous, jump off the bridge. (Brace yourself that water will not be hugely warm
).
Man .. what else. I haven't even touched upon half of my favourite things out there. Ok, here's one, but it's dependent on time and budget because the ferry ride isn't cheap, but it's worth it. The northern Gulf Islands of Denman and Hornby are reachable by ferry and the terminal is going north towards Comox (a little bit north of Qualicum). You take a ferry to Denman and you can spend a little time there, or cut across and take another ferry to Hornby. The lifestyle of these islands is really something to see. On the far side of Hornby is a day use only provincial park called Tribune Bay. On a sunny day this place is just MAGIC. It is this beach of pure white sand by a bay framed by rocks along each side that has some incredible snorkeling. On a hot day you could be forgiven for thinking you were in Hawaii. (On a not-so-hot day, maybe not so much, but it's still a very pretty spot). Boats take safe anchorage in the bay and you will look longingly at those boats, wondering, look at those losers with boats. Why can't I be a loser with a boat? Instead of a loser on the beach looking longingly at the losers with boats. What is UP with that! ... ANyhow if you're lucky, you might find pretty naked ladies riding horses in the water (I did warn you that the lifestyle of these islands is something else .. and I'm not making ANY of this up.)
It's a little out of the way but Carmanah provincial park is also a magical spot. You probably don't want to put this on your itinerary though unless you have a lot of time.
You should book a "ferry" ride from Port Alberni to Bamfield (and back). The MV Lady Rose, or her sister the MV Francis Barkley, are ships right out of history and the ride is amazing.
I have been exploring that place my whole life and haven't gotten bored, or barely scratched the surface of it yet. There's Spider Lake. Or go caving at Horne Lakes.