My wife and I are one day at a time type. More than once we have altered our entire pre-planed trip and done something else. Last summer we were headed to Montana and Wyoming and ended up spending the entire summer bumming up and down the Oregon coast. Sharon my DW would check for a campground a couple of days before we had to leave a CG and find a couple of days here and a week here or there.
We have made reservations for specific things like Quilt Week in Paduka, KY or Spring Break week, but, very seldom.
We are both retired and in our mid and late seventies, heat has become very hard to tolerate for more than a couple of days at a time so we try to avoid more popular summer spots like beaches and lakes. We spent 11 weeks circomnavigating the US. Two or three days traveling and two or three days in one place. Twice in that time we did Home Depot camping but we left hone in mid-Sept and returned home Tuesday before Thanksgiving. We never called more than three days in advanced for a spot and only called then for week-ends.
You just have to find the way that works for you.