If roostering the HammAR is like goosing anyone else, I'd be very careful about that. Expect elbows to fly and other objects to follow. Pay up your insurance first

How to train for a Steel Shoot, The plblark first of the year version.
Go pick up 2 random strangers. Drive them all over the county.
Drive through white out conditions in March ... Maybe go through the car wash but leave before the rinse?
The hell with learning that GPS or the exact address ahead of time. It's much more fun to find in whiteout conditions from a google maps printout. Make decisions by committee. Take all the blame.
Mud. You'll need lots of mud.
How you get the 2 ' of mud into the freezer is your business!
Follow EAJuggalo's example and practice in loose shoes.
Carry heavy cold items in the snow. Figure propane tanks or something.
Shoot a lot but poorly. Blame it on the cold. Be disbelieved. Imagine that

Have random strangers abuse you on everything
Repeat in reverse order
Have your wife yell at you when you get home because you stayed too long
Then SMILE because it was so damn much fun!