Minooka Park , Wilson Lake, KS

We just made reservations here for a stop over on way to Utah in June. We just received our confirmation and notice check in time is not until 6PM! Wow I never even looked at check in time cause usually it is 3PM. Has anyone camped there and what is the chance of checking in early afternoon? We are considering cancelling reservation cause we will be thru that area much earlier than 6. Any info would be helpful. Thanks, Tara