The obstacles aren't the hard part for me, in fact they are easy when compared with the desert heat and getting through the hills out here. The obstacles are more a battle of will- I'm terrified of heights and they want me to climb HOW far into the air and then jump?!? Yikes.
I didn't bring any water (stupid, stupid) because I thought it would be too hard with the obstacles. My advice-- FIND A WAY TO BRING WATER! Seriously, the little stops they have with water are too few and far between.
Another piece of advice- train on similar ground as the 5k will be. For instance, mine was in the mountains/desert we have outside of vegas. I trained on mostly flat ground- WOOPS!
It's super fun to be chased by zombies though