Here is a great resource that covers your questions and a lot more. Describes century training plans for 8 or 15 weeks.
Distance Cycling: John Hughes, Dan Kehlenbach: 9780736089241: Amazon.com: Books
Well worth your fifteen bucks. I used a general approximation of the program for a super randonneur series this season and it worked great.
About sleep and performance anxiety, an established meditation practice is very helpful. There is some good treatment of this in the book where it describes visualization techniques.