Ultra runners, need your advice!

Okay all you long distance runners, I need all the help I can get for the run portion of the double iron. The furthest I have ever run was 31 miles and that was on trails and with no swimming and biking before hand. Anyways, I'll be hitting the run sometime in the middle of the night; therefore, it will be dark. The race site mentions carrying a flashlight for the run. Do you think that is a good idea or would a headlamp work better. Any particular brands of flashlights/headlamps you prefer? I already have front/rear/helmet lights for the bike and they run on double A and triple A batteries.

Also, it's going to obviously be a LONG run for me, completely on asphalt. Should I think about buying shoes a half to full size bigger to switch to in case my feet swell? How would I break them in, since they will be too big ordinarily? What about blister control? I rarely get blisters on my feet anymore, even during marathons, but I'm sure it will be inevitable here.

What else should I be thinking about? Good resources on line to look at? I looked at ultrarunning.com, not seeing a whole lot about training, etc. there yet, but haven't had a whole lot of time to really go over the site. I will be starting a run/walk routine during my long runs since there is no way I can run the entire way and I think I got the nutrition thing pretty much hammered out (until it collapes and then it's on to Plan B, C, D...). Thanks for the help and suggestions!