How many make park reservations vs find as you go.

We simply do it both ways as circumstances dictate. Busy holiday or summer weekends we will book in advance, otherwise we will wing it most times although we at least know which parks we plan to stop at. We don't fret too much as state and COE parks in our region have about half of their sites that can not be reserved in advance, even on busy weekends just show up a couple of days early and choose a first come first serve site, then enjoy the peacefulness until the crowds show up.