to me the purpose of bicycle touring is to have the trip of my dreams which is not only about the distance but enjoying the country I am visiting.
I do a lot of research with guidebooks and on the internet. Much of my bicycle touring is in Europe so I head for intesting places to sightsee along the way. After 10 years of bicycle touring I have found that if you do not plan you end up missing interesting things along the way. Regarding accommodation, I either pre book or at least have a list of possible places. Also as I am leading a group of 4-6 cycling friends I listen to their needs, often we pull into a town and head in different directions for a set number of hours (I am not a museum but some of my friends are).