Personally, I think the guideline about getting to the airport 3 hrs early is to give you some lead time to ensure that you don't get stuck in traffic and to ensure you can get through any bottlenecks at check-in or security. Walks to some gates are a bit of a trek too. If you're flying during a weekday morning, you might want to leave for YVR earlier if you get stuck in tunnel rush hour traffic for example. (I almost missed a morning flight because of an accident on a bridge.) If you have a first class ticket, I wouldn't worry too much about bottlenecks at check-in or security because as others have mentioned, you can get to use shorter queues.

If you stay at the airport hotel, you can use one of the long term lots at YVR. (And make sure you use a coupon.) I use Park'N Fly and the YVR Long Term Parking lot (though never longer than a week). They're both fairly similar distance from the terminals and offer free shuttles to and from. At Park'N Fly, you just drop your car off in a drop off lane, have staff park your car for you, sign-in, and wait for the shuttle to pick you up outside the building. They have your car waiting outside the building when you return. At YVR's lot, you just find a stall for your car in one huge parking lot and wait for the shuttle at a designated pickup shelter. The most glaring difference IMO is that your car is somewhat more "in the open" at the YVR lot but I haven't heard of anyone getting their cars broken into there (both lots security patrolled and have a gated exit).

http://parknfly.ca/spring2007/vancou...er.html?=61968

http://www.yvr.com/guide/parking/
http://www.yvr.com/pdf/guide/yvr_web_couponJan06.pdf

Prices are somewhat similar but it seems weekly parking is cheaper at Park'N Fly but daily parking is cheaper at YVR's lot.