As if anyone needs an excuse to hit the road in a Scamp... I learned about this couple's blog about their travels on the Lincoln Highway and Yellowstone Trail auto routes and thought it might give some of you ideas for a trip or two as well. They made the trip towing an older pop-up camper. I loosely followed the Yellowstone Trail back from Theodore Roosevelt National Park on my trip last month and it was certainly a more comfortable and relaxing route than the interstate (which I took on my way to get to the park).
The blog is http://afordonthelincoln.blogspot.com/ if you'd like to learn more about their trip.
I'm also a member of the Yellowstone Trail Association and they've just updated their website with detailed maps of the trail. I know that Wisconsin has a detailed printed version you can pick up along the route and there is also a nice combined print version for North Dakota, South Dakota, and part of Minnesota too. http://www.yellowstonetrail.org/