Toronto!!! We use to visit Toronto every summer when we live in Ohio.
It is doable to stay in the city and still be able to go all these places including the parks. Bofore I get into that details, I have heard good thing about this hotel suites:
http://www.grosvenorsuites.com/ Never been there myself so cannot comment but it is a good location to all the places you mentioned.
Now as for the city, you can get to it easily from the city or Osyter point if want to. Just note that in the morning during week days traffic can get busy going into the city and on weekends it can be busy also. If you stay in the city you can walk to some of these places or take a cab.
If you decide to visit some other locations like Marin County for Muir Woods, or Point Reyes National Park it is also easy access from the city. To see rugged coast line of California, you can take a drive along highway 1. You can also take a day and visit Monteray Bay, about 2 hours south of the sity and while you are there you can visit Carmel also and of course if you are a golfer drive through Pebble Beach!!
The good thing about driving from the city to the theme parks is that you will be going against traffic in the AM. For Paramount it will be against traffic part of the way until you get close to Santa Clara and San Jose you will run into a little traffic. You do not need to be moving from location to location.
Since you are from Toronto, Paramount here is not much different from the one in Toronto. Just a few different ride if I recall correctly.
Please let me know if this helps