Northern California - Where to ride in SF area?

I am going to be in SF Sunday and Monday for business and decided to take my bike. Is there any decent loop to ride in the city that is relatively safe or do I need to drive somewhere north or south for a ride. I am actually staying next to SFO airport, but am meeting a friend in the Marina district on Sunday. I also have a meeting in Burlingame on Monday and could do a ride in that area as well. Looking to do a 40-50 mile ride, no more than 4000 vertical. Thanks in advance, any suggestion is appreciated.

Here are a bunch of cue sheets (http://www.velogirls.com/resources/routes.php#north) for local rides. When you're in the Marina, look at the one entitled "Tiburon Loop From Presidio Sports Basement."

The Presidio Sports Basement is a sporting goods store less than a mile from the Marina Green.

Are you staying in San Bruno? I can take you on ride Monday evening.

Here are a bunch of cue sheets (http://www.velogirls.com/resources/routes.php#north) for local rides. When you're in the Marina, look at the one entitled "Tiburon Loop From Presidio Sports Basement."

The Presidio Sports Basement is a sporting goods store less than a mile from the Marina Green.

Thanks for the que sheets, that will definately work!

Are you staying in San Bruno? I can take you on ride Monday evening.

Thanks for the offer. Sunday I am in the Marina district and Monday I will be staying in Burlingame, but I have to ride in the morning before a lunch meeting. After the meeting I have to make my way down to Santa Barbara for another meeting.

Be aware that the baseball All Star game takes place on Tuesday at AT&T Park and there are street closures as a result that began on Sat. if you are going to that part of SF (which is not the Marina district). Have fun!