I hate running, but mako is right... There are very few stretches of long runs. It's actually good because it keeps the obstacles from being insanely crowded by spreading people out.
It's been a long time, but I did the last one as a group of like 5-6 people... The runs between obstacles was kind of a leisurely jog where we were still able to speak with each other. I wasn't trying to win the event or anything.
On your list above, I'd put running above swimming (only because I suck at swimming), stair climbing, MLM white women, and 80s aerobics. Also, while boxing sounds cool, I have zero interest in doing that as a part of my fitness routine.