We travel a lot. More now that we are both retired. We only make reservations for places that we know we where want to be when. Even then, I often put an extra day in the plan "Just Because". I can't think of an excursion where there wasn't at least one - "OH, let's go see that!!" This last one there were as many "Sorry, we are closed. But, we will be open tomorrow." (When you open tomorrow, we will be 300 miles away.)
When you get to traveling, there will be many more attractions than you could possibly plan. You will also have days when the planned stop just can't happen. If you pick a piece of road that takes a lot more driving than you had expected, have a plan to end the day before your planned stop. That is what Walmart, Cabela's and rest areas are there for.
As I have been a navigator (seriously - the job description) most of my life. I plan everything. I also plan that the time table will be junk by the end of the third day (if not sooner).
Matt