The ferries all have food, drinks, buffets, shops, and scenic viewing areas. Check there website for crossing times and schedules. You can also take a bus to the ferry from downtown Vancouver. The company is called Pacific Coach Lines.
You can also book tickets in advance. Call toll free 1-888-724-5223 within the British Columbia area or 604-444-2890 if you are outside of British Columbia.
Toll free within British Columbia: 1-888-223-3779