Good on ya! Give yourself a little time to recover, and you'll be itching to do another.

As far as the neck problems go, you may want to consider switching to a recumbent. It's amazing how much easier on the body the reclined position is. I switched to a 'bent two years ago after 35 years on df's. After all that time, my bike position was very well dialed, but I'd never been able to find a saddle that worked well past 100 miles. Since then I've completed my first 1200k randonnee with no discomfort other than general fatigue and sore legs. None of the df riders I saw on the last day could say that - they were all standing on the pedals and shaking out their hands. And my times are at least as fast on the 'bent as they were on the df - very solidly middle of the pack. Something to consider.

SP
Bend, OR