I did tough mudder last year and it was a blast. There are enough obstacles that you can recover from the runs while waiting to go though. You'll never have to run more than 2 miles at once. I trained by doing 7 miles twice a week but then was in the hospital for a week right before and lost all muscle. Still completed it though.
Take care of your joints during it. You'll have to jump for different heights and that jolt followed by immediately running can do a number on your knees.
Wear shoes your feet won't slip out of when you're pulling your feet out of a foot of mud!
Don't be too proud to let someone help you. It's all about teamwork! Lend a hand when you can an let others do the same for you.
Above average strength isn't really necessary. If you can go across monkey bars and pull your own weight over a wall then you're golden.
Prepare yourself for jumping into that ice. It's going to be the most cold you've ever been in your life haha. The electric shock kind of sucks too. Just feels like getting punched in the face though.
Anyways, good luck! I'm down to answer any questions you have about it
K&N drop-in & Slow
F150 F>R (The link below because I couldn't figure out how to hyperlink...)