As an engineer, I tend to put everything on a spreadsheet, timetable, i.e. plan each day weight each gram. I have been advised by close friends who have completed the AT and PCT thru hikes NOT TO OVER PLAN, but to leave some mystery in the adventure. Let each day's challenges unfold. Live in the moment of that time. Trying to do this is one of the reasons I'm doing the trail this year - to force me into some spontaneity and uncertainty. My son SOBOed the trail in 100 days in 2005 and did absolutely NO planning or training, but then he's not like most people.