I've been watching this with interest.

A great idea to meet up with like minded people to have a photo shoot.

My thoughts: 
Too much walking and not enough photography     -        6-9 miles  
I know I would probably cover this if out shooting for a day but I think this distance will at least double if you're going to be taking photographs along the way. A bit like dog miles you won't be sticking to the track but zig zagging here and there to take photographs. Average speed of 1 or 2 miles an hour setting up shots waiting for others to set up shots etc. and its gonna be a long day.

Nothing has been said about the destination what type of shots are there. What variety of shots etc etc etc  Are there opportunities to join and leave for part of the walk etc. Are there shooting opportunities no matter what the weather ?

I wouldn't want to discourage anyone from taking part, I wish you well, but this would not be for me. I am only putting my thoughts down for your consideration because there maybe others thinking the same as me, who would like to meet up but this would be just too much for.

 

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html