Yeah it is a little bit tricky. But here's how you do it.
The easiest way to get to SFSU is by the taking the MUNI line, #28 from the Daly City BART station. It runs every 15 minutes and takes 15 minutes getting to SFSU.
The hard part, of course is getting over the freeway to get there. The easiest way is to cross on the sidewalk of Daly Blvd. and then walk to Long Street where you can cross to the BART station. (Be careful with traffic it is nuts which is why a lot of people don't like this route.)
To get from Poincetta to Daly Blvd., the quickest way is through a break in the fence that takes you right to the blvd. (Assuming it is still there.) It is about half a mile from the break in the fence to the BART station.
It used to take me about 45 minutes altogether (25 minutes to walk to BART--15 minutes to ride the MUNI 28.) 1 hour if I missed the bus.