Thanks for the replies. I'm pretty commited to using my 6.5 x 7 trailer frame. It's in great shape with good rubber and since it was originally a tent camper, swhould be rated for around 2000 lbs.
I think I'll build a continuous bench seat that runs down one side of the trailer, across the front and back down the other side. It will have a back to lean against. This way I'll have maximum seating and there will be no way to fall of except in the middle back.
I'll probably build the bech frames from steel square tubing and both on some wood for the seats and backs.
I'll probably have a high pole at each corner of the trailer so I can string lights on it. Can anyone tell me how to run lights from a 12 volt battery?
For halloween, I'll leave the FEL on the tractor and put a scarecrow in there that looks like a corpse... this should be fun!