Have you had a look at the Long Distance forum? You might want to post your questions over there:
http://www.bikeforums.net/forumdispl...urance-Cycling

When you post in the Long Distance forum, you'll need to provide more information:

When is the double century?
Your current max is 130 miles ... when did you do that?
What do you normally ride in a week?

And no, 200 miles is definitely NOT 3-4 times more difficult than a 200K randonnee. In fact, I found doing my first 300K randonnee (323 km = 200 miles) about the same difficulty level as a 200K (125 miles) ... just longer.