Did some checking regarding launching and overnight moorage in the Campbell River area. You can launch at the Spit as Nancy H has suggested. I spoke to the people at Discovery Harbour Marina, which is right downtown Campbell River and they are presently building a new ramp which may be ready for the 2005 season (
http://www.discoveryharbourmarina.com ) and they have parking and moorage.
Just south of Campbell River is Salmon Point Resort (
http://www.salmonpoint.com). They have RV sites, cabins, launch and lots of parking. This might be your best bet.
The run from Campbell River to Desolation is not long or difficult and a lot of people from here go over for the weekend. The Strait of Georgia can get rough, but most days are pretty good in the summer.
Some commercial charters to Desolation Sound take off from the Comox Marina. There is a good boat launch run by the Town, and moorage is available through the Black Fin Marina.
If you decide to come to Vancouver Island and leave from here.... give me a shout and I will be happy to run down more details.
Del