For those seeking the truly epic.....

[572cv]

...this ride down the length of Vermont should do it for you.

http://100-200.org/

Out of my range, but I've ridden lots of it, a beautiful route!

[nova]

Looks sick, far from the easiest double century but surely a beautiful one.

[dustyrider]

I was looking at the training tips page, since I was wondering who does double centuries that doesn't do double centuries, and found a quote to be very amusing.
"Do your homework, but remember, strong legs and the ability to stay in the saddle for 200 miles are not the same thing! A mix of LSD (Long, Steady Distance) and high-intensity training is best for most riders."

I work in an environment where everything has a 3-4 letter acronym, and we all invariably end up having to tell someone what one of them means.

LSD (Long, Steady Distance) is one they absolutely need to define each time!

[thinpin]

Sensible people would enjoy such a route over two days! ;)