Muni's pretty easy. And as Shooter says, if you're willing to climb some hills, the city's actually very walkable. SF is a small city, so you can get to wherever you want to go without much hassle.
For beer things:
Monk's Kettle is literally 2 blocks from where you're staying. They have a pretty nice selection. Toronado's about a 20 min walk. I also love Magnolia, in upper Haight, which is about 10-15 min from Toronado.
Non-beer things:
There are non-beer things?! Ok, kidding - I second the Exploratorium. It's a one-of-a-kind place. It's also pretty close to Chrissy Field, which is a great place to walk and will take you right under the GG Bridge. Definitely walk around Chinatown (and get lunch or dinner at House of Nanking! Don't order off the menu, just ask them to bring you stuff!) and North Beach. Go up to Twin Peaks and admire the view. Walk down 24th st in the Mission. Grab a burrito and look for Balmy Street - it's a little alley off of 24th where people have been painting awesome murals for years and years. Try to get some Blue Bottle coffee, or, if you don't have time, Ritual Coffee (which is very close to where you'll be staying).
If you really want something special, take a day and hike around the Marin Headlands. Make sure you hang out until late afternoon, then find a place to sit and watch the fog come in over the GG Bridge. It's amazing.