I once flew to SF first class on Delta, not bad. But if you can fly business class on United on their new Dreamliners (787?), you'll enjoy it tremendously. I made a connection from Denver to SFO on business class and sat next to a captain who was flying to SF for his next shift the next day; we had a nice chat.
I like the Hilton but The Westin next to Union Square is fabulous and it's more convenient. You can take wine bus tours to Napa. Yeah, you don't need a car. Use Uber or Lyft; there are way too much construction going on (like Montreal).
SF has its own weather. Summer can be nice but the weather tends to be the coldest depending upon which part of SF you end up in. So, always have a warm jacket with you, which will make you look like a local. If you travel in SF without a jacket (in your hand or on your body), locals will treat you like a tourist. But once your get out of SF in the Summer, it can be pretty hot and warm. SF tends to get Indian Summers (meaning, the hottest months usually are late August, September and October).
You should take the ferry to Sausalito and Tiburon. Again, take a warm jacket with you. But it almost always never rain in the Summer in SF.
As for hobbying, I can't help you. Sorry. The SP's are way too expensive in SF especially because of the rich tech dudes who can pay high $$$ because they get free food (cooked by gourmet chefs) all day long at work. I'd recommend you hobby in Montreal until you are exhausted
before your trip to SF.