What have I done?

Do you sometimes find yourself in a situation where you say, "What have I done?" I'm not quite sure I'm there but fear I am on the precipice. Here's the deal:

One of my good friends, I've mentioned him here in the Den before, Jeff is an ultra-marathoner. By ultra-marathoner, I mean he runs 100 mile marathons. And not on flat surfaces, but trail running. I had mentioned to him that I'd like to crew one of his races. Well, that time has come. He's racing the Kettle Moraine 100 in Wisconsin this weekend and I will be his crew of one (1) for the 24 hours plus of running. After reading the 45-page manual, I went over to his house last night and we went through all that I need to do; hence, my position on the precipice. Or the fact that he wants me to pick him up at mile 62 and run eight miles with him. Yeah, I think that may be it. No, I know that's it. Mile 62 is critical for him - just have to get him through that eight mile stretch. Yikes.

Here's the deal - that's a distance I've net yet run. Certainly not in the early evening and certainly not on a trail carved by glaciers how many millions of years ago. So I ran a 5K tonight to prepare - oh man, I better be ready. We start at 6AM on Saturday.