Where was Maniac when he found Russell and Piper?

After Maniac Magee lost his dear friend, Grayson, he set off on his own again.  He went all around the surrounding area.  It was wintertime, and he needed to find shelter.  He wound up in Valley Forge, Pennsylvania.  He came across the open-air museum at Valley Forge, where the "only buildings... were tiny log-and-mortar cabins, replicas of the army's shelters."  Feeling like a cold, weary, and defeated Revolutionary War soldier, Maniac wrapped himself in a blanket and settled in to one of the replica cabins.  In the middle of the night, he heard voices coming from outside his temporary home.  The voices were arguing and calling each other names.  Maniac did not know who the voices belonged to.  He soon got up to find out.  In the cabin next to his, Maniac found "two little boys" named Piper and Russell.  These boys, who were brothers, were running away from home.