Biking is a lovely way to experience the city as SF is an extremely bike friendly place. Moreover, the SoSf guide(BB) was extremely passionate and knowledgeable about the city. Even if you don't bike on a regular basis, this tour will suit you just fine as it is not very vigorous exercise and you do a fair amount of "wiggling"(avoiding inclines). I would advise doing this tour in the beginning of your visit since you cover a lot of territory and may discover places you might want to return to.