not dumb at all, i was in the same shoes last week before the Lost Trail Race
i think the key was(as suggested to me by racer220) keeping the sled as stock as possible
mandatory things:
helmet
tekvest
knee pads
tether
snow flap that is 1/4 in thick, 1 in wider than the tunnel on both sides, and touches the ground when the rider is on the sled
for stock class you can:
put screws in your track(needs tunnel protection from screws)
revalve your shocks
and that should put you in good standing for the stock class(there is more i just cant think of it right now)
the stock class motto is "stock is stock" so the sled should stay the way it came from the factory(ex. a arms, track,exhaust)
then you can bump your sled up to the improved and mod classes if you feel like it(i suggest it for more seat time on the course)
it is an awesome experience to say the least, lots of very nice/knowledgeable folks to chat with and get ideas from
Just be warned, You will most likely be hooked!
Skisucca
p.s. read the rules on the rmsha website, slp sells the isr rule book also