The 63rd World Science Fiction & Fantasy Convention was being held in Glasgow in 2005, so I saved up some money, and spent even more, and went to the United Kingdom for 3 weeks in August. Aside from the time at the hotel in Glasgow for the convention, I only booked a rental car for a total of 8 days. I used the Book-A-Bed-Ahead service of Tourist Information to find rooms in Bed & Breakfasts as I decided where to go.
This allowed me to indulge myself my favorite way to travel, Making It Up As I Go. This works better when limited to fairly small areas, so the United Kingdom is very well suited to it. You can spend most of the day exploring a region, then drive a couple of hours (or less!), and be in another region full of interesting places to explore.
Of course, there is a downside to this. Because I have to spend time each day traveling, I have less opportunity to explore a particular place. This means that everyplace I go, there was more I wanted to see, but did not have enough time. On the other hand, if someplace was really appealing, I was able to stick around a little longer without worrying about meeting an appointment.