I just did this in Nebraska on June 9th. I hate running, did basically no training, but I had a BLAST & would definitely recommend it to anyone who gets a chance.
The worst part for me was how hilly the course was. Apparently they went out of their way to find the hilliest ground in Nebraska! They say each course is different, but ours started out with about a mile & a half run mostly uphill.
The obstacles were the funnest part for my group, especially the giant mud pit at the very end. I'd also highly recommend dressing up. I kind of had a Joe Dirt thing going on, & let's just say I got some weird looks & funny cheers.
Just try to go with somebody that will be at your pace. We walked quite a bit of it, & we definitely weren't the only ones. I think our final time was just a few seconds over 49 minutes. Have fun!