My mum and I spent a weekend in SF and the weather was amazing when we were there - exactly the kind of weather I wish SG had all year round. I love walking around downtown too (I love doing that in London too), something I wished I could do in SG but there isn't really somewhere like that in SG that allows for it, and the heat is just horrible.
We stayed in Hotel Zetta in SF and it is really cool. Seriously, really really cool. The location was pretty good (near tons of shopping and transport) and service was great. The view out the window was a wall of graffiti but we didn't mind that at all (we all know I love street art). The interior decor of the entire hotel was really nice and the bathroom is probably The Best bathroom I've ever had in a hotel room. Super clean and bright, and extremely spacious.
We spent the first day in SF shopping and I spent so much time in Old Navy picking out tees (guys section, of course) which are now some of my fav PJs. Also spent a bomb in Club Monaco but hey, at least everything was in the sale (that's just what I told myself when my cc statement came haha).
And no, we didn't take the tram up/down the slopes at all! Walked everywhere. I suspect my mum secretly hated it oops.