A run in the woods?

I have given some thought to a variety of possible adventures for this summer and one of them is an ultra-running adventure that I will disclose at a later date after I discover its feasibility.  One self-test I will do to determine if the Ultra-running is possible is a 24hr test run with a very light backpack.  I really have no idea what kind of distance to expect and how much pain I will be in.  The most I have run consecutively is 26.2 miles which could easily be completed in 4hrs, but how many miles can I go beyond that?  Working as a paramedic I am use to going long periods of time without sleep but how will I do when you add the physical stress of an intense training exercise?  If I ran the first 26.2 in 5hrs and slept for 3hrs I would have 16hrs left.  I could walk the remaining 16hrs at 2 miles per hour and in theory complete 58miles.  So based on that rough calculation I would like to do at least 60miles but we shall see.

The test run should take place in an off road environment that I am also familiar with.  I figure if I know the trail well not only will I be faster but I will also have less of a chance of getting lost as I will be quite exhausted.  I figure possible locations to be Zaleski state forest which provides a 24 mile loop trail with water available on site and plenty of elevation change to challenge me.  Another option is Alum Creek state park which has a mountain bike trail of only 6miles.  The trail is much closer to home and a lot flatter.  The advantage of Alum creek is it would provide me a staging area and a point where I could request support from my small network of friends and family.  I figure a three day weekend will be needed so that I can have a full day of recovery.

I plan to bring a pack similar to what I would expect to need on the longer expedition.  I’ll pack an ultra-light pack, thin summer weight sleeping bag, Thermarest sleeping pad, and a sil-nylon tarp for shelter.  Extra equipment to be included, food, water, camera, head lamp, knife, and a thin rain shell. 

I hope this minimal overnight gear will be adequate.  I will do what I can to provide a brief video pre, during, and post update.  Wish me luck and any advice will be greatly appreciated.  Are there any adventure racers, ultra-marathoners, or endurance athletes out there?