One of the best pieces of grooming equipment for
behind a snowmobile is an old box spring. I used
to procure them along side the road on garbage day
in da UP, eh. They are very effective for leveling
small bumps in the trail, by picking up snow and
dropping it in holes. In wet snow, this is a problem.
A piece of chain link fence also works well, just use
a chunk of pipe or rerod on the leading edge and a chain
to pull it. It levels things out nicely.
Using a metal frame help level things out and can help
in deep snow and for grooming things wide in one pass.
We built a five foot wide unit about 12 feet long, just
two pieces of angle iron with four cross member and a
ramp on the front to get up and over the snow. It would
bend a bit when trees were hit, but you just had to hit
one on the other side to straighten it out. It was light
and could be towed by the snowmobile pretty easily. It
needed the chain link fence behind it to prevent leaving
to smooth of a surface.
A track setting sled isn't too hard to make as well, depending
on how hard your snow conditions will be. For soft snow
just a steel plate with the properly shaped rails on the bottom
will do the trick, make sure it is long enough (maybe 3 feet long)
to be stable at reasonable speeds. For harder snow it will
need to cut the track first.
Good luck. The most important thing to remember is not to load
down the machine too much, digging is not that much fun.