So, you'd be traveling on the tour bus only? That means you couldn't get reimbursed for airfare or car travel...what about lodging?
The question is who are you doing it for? What are their goals?
I'm gonna take a whif at this one...
My guess is that their pockets aren't that deep. Coupled with the fact that some folks would volunteer to do it or do it for next to nothing, you're looking at $100 to $200 a day plus expenses (film? & lunch only probably) for a full day of shooting.
That's my best uneducated guess. Of course, it's hard to put a dollar value on the shooting talent and notoriety of the Jakeman.