I think as long as you're prepared to camp, go-with-the-flow makes it a lot more relaxing. But these days, hotels tend to book much closer to capacity than they used to. (Now, at this exact point in time, with the economy being so depressed, maybe that's not as true as it was two or three years ago.) We've had at least three experiences that I can remember off the top of my head, when we've been touring on the motorcycles, pulled into the town where we intended to stay, and come to find out that everything within a 50 mile radius was booked. Not fun and not particularly safe when you're exhausted at twilight/after dark on a motorcycle. Not even possible on a bicycle.
So I definitely wouldn't count on hotel facilities without a reservation. But what we often do now is just make a reservation at someplace where you can cancel the same day. Even calling ahead in the early afternoon is almost always enough. As long as we pay attention to what time it is, and cancel if we need to before the deadline when we have to pay for the room, it kind of gives us the best of both worlds, planning-wise.
Speed comes from what you put behind you. - Judi Ketteler