The Rat - My wife thinks I am mad too - your wife though does have a point - 6AM on a Sunday!!!!
As for your run 20.5 miles! You certainly have the mental strength to succeed (6 am in the rain too).
Ultimately, you know you body and are the only one that can listen to it but it sounds like you have a good idea what you are doing with the 3 month lead in etc Power to you.
I too train alone as I like to fit it round work and home life plus there are not too many guys in this area who could come out for a sub 2 hour 17 miler training run on a Sunday (6:56 average with 1800 ft ascent). You got me thinking yesterday maybe I need to train a bit harder on the long runs....
I'm up at the lazy time of 6:20 tomorrow to get in 35 minutes of swimming - my knees feel a little achy from today's exercise.
Lou7 - the loneliness of the long distance runner, only we know how good it makes us feel - glad my suggest struck a chord.
Keep foruming.