Just returned from a 9 week trip to Alaska and back to Maryland. Only made reservations for Seattle, the 4th of July and in Homer because we knew the dates we would be there. Other than that we "winged it". We only had trouble two nights because we hit western South Dakota the weekend before the Sturgis Bike Rally started. But even so we were still able to get a campsite for the night. Some days when we figured out how far we were going to be able to drive I would call ahead early in the afternoon to make sure we could get a site. We often drove farther than we thought we would so a reservation would not have been beneficial.