Tough Mudder!

A year from now, two friends and I want to do this. One of them is ex military, and she's run a half marathon before. The other is a frequent marathoner. Both are petite women, and tough as nails, with some measure of upper body strength.

Me, I'm a 6'1" tubby girl who can easily run a 5k. I am training for my first 10k (I'm confident in my ability to do it) but I am still nearer to 300lbs than to 200lbs. A push up for me means knees down, and not all the way to the ground, or I'm not gettin' up.

I guess what I want to know is--

Can this be done? I know my girlfriends can handle it, but are there obstacles that the three of us won't be able to handle alone? Do we need more teammates?

Anyone run a Tough Mudder that started out in terrible shape like me? I am so thrilled by the idea of doing it, and I have ten months to improve myself...but I still worry that it can't be done. If you've done anything like this, going from zero to Tough Mudder, I'd love your advice. Diet, workout, anything.

I want your advice even if it's, "For your own good, don't." I'd rather have honesty than get stranded in a swamp in Florida in winter, holding back two superior athletes.