To drive, you would have to go from Vancouver to Horseshoe Bay (45 mins to an hour with traffic) then the ferry to Langdale (Gibsons), then drive up the Sunshine Coast to Earl's Cove where you catch another little ferry to Saltery Bay and then drive up through Powell River to Lund, which is about another 1.5 hr drive to Lund, the beginning of Desolation Sound. In the summer, the ferry lines will be crazy so get reservations for sure. The flight is direct so would be a lot faster and easier and the ferries plus the drive time is looooong (including waiting time for the ferries) but the scenery, especially the ferry from Earl's Cove to Saltery Bay through Jervis Inlet is spectacular. The two ferries align when you reserve but if you wanted to take a slightly later second ferry, you could stop at Egmont to see the Skookumchuck Narrows which is very cool. But it is a long day. A drive definitely worth making if you have the time and the inclination, but if time is of the essence or you don't like driving and ferries, then I would fly.