We are travelers, we rarely stay more than a few days at one place. My planning consists of choosing a general plan of where we want to go and what we want to see. As our trip progresses, we make changes as we learn about things near our proposed path.
A couple of hours before we want to stop, we start looking for a campsite, usually using Streets and Trips on our computer. Very rarely have we had to go to a second choice. On long weekends, or in crowded areas, or if there is only one campground in the area, we might phone ahead.
Usually, our campsites are little more than a place to sleep. As a full timer, you may want more from your campsite.