People tend to check in during these times:
Huge off-leash dog park, also known as Doggie Disneyland. With miles of trails and swimming areas for the dogs in both the Sandy and Columbia Rivers, prepare to stay for hours.
Leave your valuables at home, do not park in the RV parking spaces without a boat or RV even if the lot is empty or you will be ticketed, use the restroom before you hike, bring water and poop bags!
Bring your pooch here and he'll be super happy!