Justin leaves California in the morning (possibly sometime before noon) and therefore, would not be in Pittsburgh until sometime after 7 p.m. Since it is winter, he would not be back when the sun is up. He's also surprised that Brett was up when he comes into the kitchen. This would be early morning (possibly 8 or 9 a.m.) which would make the time in Pittsburgh either 11 or noon so he would never make it back to Pittsburgh before sunset.
When Brian and Michael have fallen behind due to Brian's injury, they stop in front of Whitevale Cemetery, which is in Ontario near Pickering. They had already entered back into the US earlier.