I am a first timer at the outlet. The reservation site did not ask me how many vehicles but when I checked out it said zero. We will have 3. Should I call the office?

Outlet park is Corps, so no state park fee. You can just talk to them when you check in. I've never had problem with number of vehicles

Kansas state parks have a daily fee you have to pay per vehicle on top of the site reservation. I believe it's $5 per day or you can buy a yearly pass for $25 per vehicle