I am not sure if you are asking where Maniac went at any particular point in the story, but here is a brief rundown of his ramblings throughout the course of the narrative:
Maniac was born in Bridgeport, Pennsylvania. When he was three, his parents were killed and he was shipped off to live with his Aunt and Uncle in Hollidaysburg. At age eight he ran away from Hollidaysburg, and no one knows where he was for a full year. After that time he turned up in Two Mills.
Maniac appeared at random places in Two Mills during his first two days there. He met Amanda Beale, and was invited to join her family at 728 Sycamore. He stayed there until people resentful about a white boy boy living with a black family left hateful graffiti on the Beales' wall. Then he left town and ended up staying at the Elmwood Park Zoo.
At the zoo, Maniac is befriended by Grayson, who is a maintenance man there. Grayson and Maniac move into the baseball equipment room near the band shell in the Park. The two live amicably together until Grayson dies.
After Grayson's death, Maniac wanders aimlessly in Two Mills and the surrounding communities. He ends up in a replica cabin at Valley Forge, where he is adopted by the McNab boys. He stays at the McNabs awhile, but eventually is forced to leave and wander on his own again. At the end of the story he is found again by Amanda Beale, who, in no uncertain terms, tells him that he is going to go back to live with her family.