You don't mention what time you land at YVR, or your transportation to Canada Place, or your nationality, or your sailing time. So.... here's my general advice: allow at least an hour at YVR to clear immigration and get your luggage. Allow at least 35-45 minutes to get downtown (either taxi or skytrain). If you find a porter and drop your bags at Canada Place, plan on 1-2 hrs (when you return) to get thru check in, security, and US immigration. You must be onboard 90 prior to sailing. You do the math...