What questions should I ask?

LRussoPhoto

I was approached by an organization who is having a mud run style race and would like me to photograph it. They had this event last year as well and I contacted the organization prior and asked if they minded if I came and took photos and then sold them on my Smugmug site and they said it was fine. I shot the event and was happy with the sales and the organization was very happy with the quality of my photos.
So I was just contacted by them and asked to set up a meeting to discuss me shooting this years events. I have shot a hand full of these types of events over the past year as well as shooting many motocross style events over the past few years. All pretty much by contacting the promoter and asking to shoot these events and selling the images on my own. I have never been paid a fee to shoot an event.
So my questions are, how do I come up with a fee and more importantly what questions should I ask the organizers of this event in order to figure out a rate to charge.
To clarify, I am a one man show with 2 cameras, with one 70-200 2.8 and one 18-200 3.5-5.6.
Any help would be greatly appreciated.