SF on a Sunday is ussually not too crowded. Ive been and the mornings are VERY slow because of people going to church and whatnot. But in the afternoon it starts to pick up.
On Sundays I ussually get there when it opens, ride the big things first before it gets crowded, eat, chill out throughout the afternoon (water rides, flats, games, ect.) then at dusk the park like empties and thats another good time to ride some big coasters without killer lines.
PS,
This belongs in the SFGAM section of the forum.
Dallas Cowboys 5x Super Bowl Winners