If the place is still going I think I would be up for it, I've always fancied it and i've been getting something that is apparently called a gravel bike which hasn't seen much action yet.
Not sure about my athletic ability but I can usually huff and puff my may through so I suspect I could keep up. Would give me some motivation to do a bit of training before hand.
Can you send any details on the finer points?
Sounds like the ideal bike for this ride. Most of it is on country lanes or dedicated tracks.