I did the Warrior Dash two years ago and can say this. Be prepared to toss nearly everything you wear. Especially shoes.

I kept a pair that were past running time just for that then switched to flip flops after. They had water trucks for rinsing you off but unheated water so it was cold. Yours may be different since not the same race. I brought shorts/bra/shirt to change into but had to do it at the car.
Note: it stormed for two days prior to our Dash so the entire area was a mud pit, not just the course. We were muddy before even starting.
Not sure how you'd train for the obstacles. Ours were scrambling over cars (frowned upon in our town), scrambling downhill, walking on and going over logs, scrambling back uphill (there were ropes), wading thru knee deep muddy water (something I normally avoid), hopping over "ruins", crawling thru cement pipes (see muddy water comment), climbing up & over large hay bail pyramid, then of course the fire jump (duraflame logs - not that high), moguls and the final mud pit.
I will provide this warning -- if you can find cheap/old cycling gloves, use them! The cement pipe and the mud pit both had sharp/rough objects that cut up our hands & knees. I crab walked thru the pipe to keep my hands up but not possible in the mud pit. The same thing happened to friends who did the same type of race in other cities.
All that said, it was a fun. My son, his girlfriend and other friends are doing it this year.
Don't over stress the obstacles. They will let you go around and keep going. My husband had an open wound on his hand so was not about to do the mud and it was fine.
Oh, one last note. Sunscreen. All over. Friend and I had tan marks from where the mud had not covered our arms/faces.
