Dont get too worried about the ladder lift, you'll be able to do it with no training at all, im sure my nan could do it!
Enclosed space, dont try and remember any of the route, just feel everything and follow your hands.. There's a bit that feels like a dead end but it's actually a bit you have to get low and go under..
First run through is with vision, then they'll cover the ba mask up and you'll do it again in reverse.
Casualty drag is easy, they guide you so just take some nice big paces.
Killer is the equipment carry, just pace yourself, it's about stamina not pace.
I did the tests with no prior training, no gym etc and was fine.