In talking with my friends and work and online about my trip planning, something finally sunk in and I had an epiphany of sorts about this trip. Without a specific reason or a deadline to come home, I don't have to limit myself. That's such a radical departure from how I have always taken vacations - I have a set amount of time and I fill up that time with whatever I can.
On this trip I can stay an extra day or leave early. I can take a long scenic trainride that shows me the countryside and allows me to stop in small towns along the way, or I can take a faster (more expensive) train that gets me there sooner so I see more at my destination. I can take a day off when I'm feeling burned out.
A friend at work suggested that rather than book hotels far in advance, either book online a couple days in advance if I know when I'm going to be somewhere or have a list of a few hotels/motels/hostels that I can try when I get to my destination. My style of independent travel is to read what the guidebooks have to say and their suggested itineraries, pick and choose what I want to see and put them in a rough order, and then be flexible. That worked out pretty well in Australia & Hawaii in 2002 and China/Korea in 2009, and yeah, I missed some things because I was doing something else but that's what happens sightseeing in a new place.