The Twelfth Doctor - and OPEN to everybody
The Doctor would've spontaneously visited Bill Potts [info]girlouttatime, materializing his TARDIS inside her apartment if need be, and invited her to join him for a day in the park.
Part of the time would've been spent checking out the carnival.
The other part of the time, he would've found a shady spot, away from the stage (where he TARDIS is parked), sat down upon his portable amplifier and played guitar, chatting with anybody who came by.
During the fireworks display, he flew the TARDIS into the sky above the city and hovered there... then climbed out and sat on the TARDIS' roof to watch the fireworks from an unobstructed, bird's eye view.