"It's not your legs it's your stomach"

Next Saturday I will do something that on the face of it sounds foolish. I will run almost twice as far as I've ever run in one day - 50 miles. And who knows? It very well might be foolish. But, I have some reasons to be confident. I've gotten some good advice from Baltimore ultra/triathalon "cover girl" Alyssa. I'm pretty much going to follow her nutrition plan - which is 1) drink one bottle of fluid (water, gatorade, or combo) per hour 2) Eat an energy gel every half-hour 3) Take a sodium/potassium pill once an hour 4) Have my wife ready with some "comfort food" if I start feeling bad.
The other thing that makes me feel confident is the training I've done the last several weeks. The first weekend in November I ran 20 miles on Saturday and 20 miles on Sunday. I actually felt pretty good on my Sunday run until Arjun reminded me that I would be running all 40 plus another 10 in one day. I have to admit I was so sore the next day that I couldn't run - but, I didn't drink or eat much during that second 20 miler.
The very next week I ran a full marathon at Harrisburg. The plan was to run just under 3 hours - but, I was feeling strong and I kept seeing people who I didn't want to beat me (guy wearing headphones, guy with no shirt etc) - so, I ended up running a 2:47. This time I stuck with my nutrition plan as described above. The best thing is that I felt almost no soreness the next day - which showed how proper nutrition can be critically important for runs over two hours.
Also, I heard a man and woman near me at the start line before the marathon talking about the JFK 50 miler - so, I chimed in that was running my first one this year. The woman said that she concentrated so much on the trail section in the first 15 miles (it's rocky) that she didn't eat or drink enough - and felt awful later. The guy said that a lot of first timers make that mistake - they have the legs to go 50 miles - but, they don't have the stomach. They get tied up - can't eat - and then they completely bonk.
So, I feel pretty good since nutrition is going to be my focus. I probably won't even measure my progress in miles, but rather how much longer is it to my next energy gel? or have I sucked down enough water in the last 15 minutes?
I've also run or at least seen most of the course. I ran a 20 mile out and back run on the appalachian trail section - which showed me that I will get frustrated in certain areas where the rocks seem to go on for miles, but at least I know what to expect. Yesterday I drove the last 8.5 miles that's on roads and ran 12 miles on the C&O canal path. The canal path has pretty good footing - and I think I can get going pretty well if I'm not too beat up.
When I first signed up for JFK I had no thoughts about competing - just surviving. But, I'm not sure I can run a race and not "compete". I don't know what that exactly means over a 50 mile race. I know I can't go too nuts over the trail section - because if I fall or twist an ankle it could be all over before it's started. I've even resigned myself that I'll probably get passed by some folks on the trail section. But, there's a LOT of running to go after we descend to the C&O canal path - and I figure that's where I can get in a rhythm and pick some people off. While running on the canal path yesterday I visualized hawking someone down or pushing the pace around the turns to hold someone off.
Whatever happens I'm sure it will be an adventure!