Big idea or foolishness?

So I am having delusions about running/walking in the Peachtree Road Race this year on July 4th. It's 10K. I doubt seriously I'll be able to run it and I have even greater doubts about finishing in time to get a t-shirt (55 mins), but I think I really want to do it, even if I walk the whole thing. What an accomplishment that would be! The 10K translates to 6.2 miles. Starting Monday I will be walking 2 miles every morning, isn't possible to work my way up to 6 miles in 6 months? Even if I'm the last person to finish wouldn't that be great? I've never done anything like that in my life. I should be around 280 lbs (or less hopefully) by then. I don't know, I'm going to give it some serious thought and look into how I can train for it, maybe even enlist some professional help. I have this vision of wearing a t-shirt that says : "I lost 200 lbs. This year I run because I CAN, next year for the t-shirt". How freakin' cool would that be?

Coming down from the clouds....I did my usual morning routine, got up, checked my email, got dressed, walked, came home. While I was mixing my protein drink, this sound that is akin to a freight train zooming down the tracks started to eminate from my stomach and then I got severe cramps so I hightailed to the potty and unleashed a fury few have ever known. I hadn't consumed anything execept for maybe 5-6 oz of water that day so I hopped on the scale to see where I stood. Pre-workout, 404.2 lbs, post-atomic bomb, 402.6. I guess my body wants to get out of the 400's as quickly as I do. For those keeping count at home, that's a whopping 18.8 lbs in 7 days. Should I be worried? Or is it all just coming together? For the record, had I not had a break during the holidays, this is weight where I would have been had I been consistent. I'm not going to worry about it unless this rate continues.