Measuring for the mail wagon

With the front and rear axle assemblies and wheels made, I can start to build the cabin. My research shows there was no standard type of wagon. RFD was such a novel thing, though horse wagons were not, it really was each man for himself. So, I get a lot of room to play. I set up my wheels and axles with Jebediah and one of my artist models. This total span is 17 inches from his nose to the back of the wheels. Having a very narrow space between the wheels for the mail carrier to enter the wagon was not uncommon. I'll need to make the cabin as light as possible since the axles are fairly delicate, but I can layer thin wood to get good detailing without adding a lot of weight.