First BIG Trip, Calif to Louisiana & Back: Feedback Please

We have gone back & forth about making reservations at all these CG's. We've decided that, rather than stressing about finding a place late afternoon, we will just go ahead and make reservations since most of the places we'll be staying are relatively popular. Year's ago, we could be spontaneous when heading out camping here in Northern California--no more as the preferred campgrounds get really filled up during the summer, even on weekdays.