In an interview with Entertainment Weekly, Dan Levy stated that the part where a tree branch goes through Patrick's shoe and into his foot came as he was taking his dog for a walk and he stepped on a tree branch and it went right through the soft part of his foot.
When Patrick and David arrive at the trailhead, the car's license plate reads "Township of Elmdale" at the top and "Pine Beetle Capital" at the bottom.
The magazine a patient in the emergency room is reading is the same one Ted was looking at earlier when reading about destinations for trips and the Galápagos Islands.