Is that Rumble in the Bronx? That's a fun movie.
The Tough Mudder looks a lot worse than it is. Yes you have to be in shape but it's really more about facing your fears than physical punishment. Regular folk don't naturally want to wade waist-deep into bogs of mud, jump into vats full of ice water or crawl through holes in the ground, but none of that stuff is actually
hard. You just have to grit your teeth and do it. And then it's tons of fun.
Since you're already working out you're probably 80% there. If you can build your long runs up to just 5-6 miles that should be enough for the TM. It'll be 10-12 miles but you get a lot of breaks when you do the obstacles, so it's not as grueling as, say, a half marathon. Not running-wise.
But I do recommend pull-ups. Lots and lots of pull-ups.
If you've got the shoulders for it.