I'm surprised at the sense of revelation on this thread. I do this several times a year if I get the chance. I just call it freelance touring.
I go where I fancy. I have an idea of area, such as Welsh Mountains or whatever. Then I just finish work and get riding. Maybe I'll sleep, maybe not. Maybe in a B&B, Youth Hostel, bus shelter, field, whatever I feel like. It's great, just go wherever. See a road that takes your fancy and follow it. I pretty much did this for the best part of 5 months in 2005.
I like the idea of us meeting up at a given location for a weekend.