Fox is getting ambitious with grassroots promotion of its shows. On Sunday, the network took advantage of the crowd at the Boston Food Truck Festival by pulling its “New Girl” tour bus into the UMass-Boston lot to distract the masses. The sitcom’s star, Zooey Deschanel, was not on the bus, but there were plenty of pictures of her and her castmates (including Max Greenfield, a.k.a. Schmidt). Representing the comedy was tour manager Chris Tenney, who took the bus to New York this week.