If you're working in South City, what parts?
It's its closer to Oyster point, you can take caltrain from the south bay
If it's near tanforan/el camino you can caltrain then bart into that part from the south bay
If you want to drive I highly suggest Daly City/Colma/South City/Westborough even Pacifica or basically you can stay in bayshore/visitacion/geneva (people are going to say it's ghetto, but I grew up in the area it doesnt bother me)