The only time we make reservations is if we are going to an RV park that we are familiar with. Other than that, when we pull in to an RV park we check it out BEFORE we check in. Several times I have had to drive through an RV park just to exit it and head down the road to another park. I tell the park owner/manager that I take their "no refunds" seriously and that I want to insure that their park meets my needs before I give them my money. I do use the rvparkreviews website but unless it is a recent review, things can change.
