Gosh, it's a nice day. Wouldn't it be swell to leave work early and head over to the Presidio, San Francisco's beautiful national park? (Tip: yes, it would.) But don't count on Muni getting you there. After all, you don't look forward to having to endure hour-long waits, do you? (Tip: no, you do not.) Fortunately, there's another bus that you can take to the Presidio -- it's free, it's comfortable (big soft comfy......