I spent so much time stressing about the logistics and planning every day before I even got on the trail trying to figure out exactly what day I would be in which towns, where I would camp each night, etc. Eventually I realized it was impossible to plan these things, and being on the trail only confirmed that. Part of the adventure is not knowing. Thru hiking forces you to live on a day to day basis, that's one of the things that made the trail so beautiful for me. One week you might feel like doing a bunch of 20's back to back, then the next week the terrain might get tougher or you might get lazy and feel like slowing down. My advice would be to plan out which towns you're sending maildrops to (if you are) and get those set up, I even went as far as to plan each town that I was going to stop in and carried a piece of paper with them and how many miles they were apart with me which I pretty much stuck to. Other than that, go with the flow and enjoy the trail