I'm interested in seeing Bletchley Park, where the WWII codebreakers worked. Any suggestions for how much time I should plan on visiting there? Two hours? Four Hours? More?

I've looked at the website but there seems to be a plethora of exhibits, and I'm not sure which ones are really compelling. I'm generally interested in WWII, especially in Britain.

I'd probably say a minimum of 3 hours - more if you are really into WWII or the enigma and early technology. If you have been to the Cabinet War rooms or other Churchill sites, you could maybe skip the Churchill exhibits and that would save a bit - but I spent the better part of 4 hours there and didn't see everything I wanted (and even more exhibits have opened since I visited) . . . . .

Yes, I'm very interested in WWII, and I have seen the Cabinet War rooms, but nothing else. It looks as though I might need to plan on a full day there.

I don't think a full day - but several hours for sure . . . .

Pegontheroad, Bletchley Park is on my must-visit-someday list; I'll be very interested after your visit in hearing your reactions / recommendations.

And speaking of sights near Milton Keynes -- are the concrete cows by the side of one the A roads still there? I remember doing a doubletake when I drove past them long ago, while my passenger (who had known what was coming up) laughed at me.