Oh man were to start but as you have already seen some of the province, Vancouver Island would be at the top of my recommendations as well - Parksville (Rathrevor Beach Provincial Park) and Tofino would be just two must see spots. If you enjoy kayaking you can do some pretty nice day trips out of Tofino. On the way to Tofino you pass though a town called Port Alberni that has a provincial park on a very large fresh water lake (if you are wanting to go fishing this is a hot spot as is Tofino) and up the road is a placed a few miles off the highway called Torquart Bay
which puts you pretty close to what is known as the Broken Island group - again if you enjoy kayaking this is another must go area. Port Renfrew
- Located two hours northwest of Victoria on Highway 14 is also a great spot as is the Miracle Beach Provincial Park further up island from Parksville. Cape Scott
at the northern end of the island is also well worth the trip but no rv camping in the park you can camp outside the park at the San Josef Bay campground. but its actually a 45 minute hike to San Josef Bay which is located inside the park.
Mosquito's are not really an issue on the coast at any time of the year. They are actually not really a big deal in the interior of the province either - at least nothing like what you would find in our eastern provinces.
As was stated the ferry's arent cheap so if you do it I recommend traveling via Washington state ferries to Victoria as they are a cheaper & it may save you some time at the main border line up. If you do the Washington State ferry route it will take you close to some great camping areas in Washington state as well.
The Kokannee's is another amazing area.
Wells Gray Provincial park near Clearwater BC is another nice provincial park.
A lot of people enjoy camping up through Squamish, Whistler and Lillooet area - you can carry right on up through into the Fraser Canyon from Lillooet and do a loop back down and check out places such as Manning Park area on your way back. The most common critter other than raccons you will see along that route is the Black Bear but they are pretty harmless if you dont leave food etc out for them. Even then they are pretty well harmless as long as you let them finish what ever it is they managed to steal.
You have a pretty good chance of running into a Black Bears on the northern end and west coast of Vancouver Island as well, as well as deer and wolfs. Vancouver Island also has a large cougar population but it is not as common to actually see one and in fact seeing one isnt really something you want to do and as far as I am concern it is the one critter that gives me any level of concern. The good news is that the odds of seeing one are not very high so not something to be overly concerned about - just make sure you carry a good knife in your pocket when hiking and read up on what you should and should not do on the off chance you do see one. If you travel to Vancouver Island in the spring or fall
the grey whales are migrating so its a good bet you will see a few of those big critters as well. :-) It is possible to see the killer whales any time of year on the west coast but where and when you might see them isnt as predictable.
A pretty good website to take a look through is Camping & RVing BC
as well as BC Parks