If you don't like to camp is another factor in daily miles. You need to get to a place with lodging, warmshowers, airbnb, motel etc. If you are certain that you are in an area that requires no reservations then it makes it a lot easier and you can just wing it. Assuming you have an open schedule, just ride the miles you want to do then find a place for the night.

I have never felt comfortable in doing this in the US. I have always been worried that if I get to a town there won't be any rooms. And I always have at least some schedule I need to keep so that I can make my flight or train etc.

Places like Europe really fix that problem with trains going everywhere. Ride as far as you want. Get to town and no rooms, too pooped to ride further then just jump on a train to the next town. But the best thing about the train is I know I can always get back on time for my flight. Really hard to ride far enough in a week or two where I can't get back to the airport on a train in a day or two.