Welcome to the Randonneuring club!!
This will be my 6th year of Randonneuring, and if all goes well, the BMB will be my 5th 1200K randonnee.
Your training plan looks all right, but let me ask you this ... what is the longest distance you've ridden so far since you've been cycling regularly, and what is your current weekly long distance?
And, here are some links which might interest you:
http://www.ultracycling.com/
http://www.randonneurs.bc.ca/links/links.html
http://www.rusa.org/
http://www.audax.org.au/index.asp
http://www.audax.uk.net/index2.htm
http://www.pactour.com/
http://www.adventurecorps.com/
http://www.bikecenturies.com/
http://www.big-dogs.org/scripts/bdhome.asp
http://forums.bicycling.com/forum.jspa?forumID=16
The link to my website is in my signature line below if you're interested in reading about some of the 1200Ks.