It's Just 7 miles.. Id get Polyester treated Briefs that wicked dry, better than cotton, if you need a tech solution.

I do 5 just to get from one side of town, to the other and just wear regular briefs and sweatpants..

Ive lived in SF, its not that Big.. your spandex may be OK if the chicks like watching your young backside as they drive by
and Hoot out the window .. maybe you will meet up at school (SF State?) and start a Family together..