I do it pretty much exactly how you described, look at google.com/flights and try to find something. A few things help - some idea about how many miles a route might be without having to look it up, some idea about what places or routes are often a good value, etc.

But flying from YVR is tough, for the amount of miles that you need there is nothing reasonably priced. SEA has a lot more options but the number of miles that you need is almost too much for a ride down the coast. If cash isn't a priority, the HNL trip is a good value. You can route through SFO, and may be able to route through SFO and LAX, or through DEN for about the same price if you want the miles.