My RJ is currently in pieces, but I think I know where everything is at. I'll try and take some pictures of the miscellaneous parts that you need, so you at least have an idea as to what you are looking for. I'll warn you now, the pieces won't look like much, as the previous owner had the whole tractor painted green because he thought it was a John Deere due to having clam shell like fenders.
As for the boiler plate transmission. I think they call it that, due to having the two pieces of flat steel bolted to each side of the transmission. Like a boiler, these two pieces of steel is what holds the tranny together. Don't hold me to this, as Wheel Horses are quite new to me, and I don't have the knowledge of them like I do the John Deere's. but I think I'm at least in the ballpark with this assumption.