I'd suggest a summer visit. Majority of our country is freezing cold during the winters unless museum tours or a day in a mall is your thing. Whistler, Lake Louise, Jasper and Banff are all beautiful during both the winter and summer. Vancouver is a awesome city and Toronto is like a mini New York. Haven't been to Montreal but hear it's a pretty cool city to visit.
If hiking is your thing I'd suggest southern Alberta or BC.
If fishing is your thing, it's great everywhere especially the northern praries. Amazing lakes with giant fish.
If pinball is your thing, we're friendly people who welcome strangers into our homes to play pinball. Every large city has a few great locations to play and have a Canadian brewskie.
If your username indicates your lifestyle, we should be a fully legalized country next month!

Coming from Cali I'd probably enter by Osoyis, BC. Head up to Kelowna/peach valley area, then over to Vancouver for a while. Take the ferry over to Ninamo and drive down to Victoria. The Vancouver Island drive is really nice. Lots of nice little site seeing towns along the way.