Not sure exactly what Tough Mudder is (and I can't access many websites at work to look it up) but it sounds like a mud run with obstacles?
I did my first 5K mud run last year which was put on by a local sheriff's department. I would just note don't forget about training your upper body - it is what helps get you up and over obstacles. Also, mine involved a lot of hills, so I would definitely do more hill running if I attempt it again.
I had a blast, was slow as heck, but I finished and didn't get stuck or lose a shoe like 80% of the other people seemed to.
Nov 26, 2011 - San Dimas Turkey Trot 10K (1:07:34)
Dec 26, 2011 - Operation Jack Half marathon (2:27:44)
April 1, 2012 - Carlsbad 5000 5k (29:17)
Mar 2013 - Dallas RnR Half
May 2013 - Long Beach 62 mile ride
| May Minutes: 468