Looks like a uni harvestor , predecessor to the New Idea Uni combine with changeable harveser implements such as combine, corn picker, forage harvester, and even baler I think. Tractor part with two front drive wheels and rear castor looking wheel with engine and operator platform on one side. I would expect to see one in the midwest. Surprised it would be in Montana. Combine was probably similar to small corn belt pull type combine of the early 50's but mounted on the Uni Harvester tractor invented by MM.