The latest version that Jim referenced above ends south of Scenic near Bigfoot Road. BIA 2 was on the original route but, is being paved. I need to get back out & scout another off pavement route to Custer.
For those that have ridden the TSDAT from Kennebec to Midland via the North. You might enjoy the alternate "blue" route south of the Interstate. Although, with a group it could be a pretty long day. I've ridden it twice solo, & it takes about 7 hours.
Camping is available at several places along the way. Gross, NE has a population of 2! Has a steakhouse & free camping across the street in the park. It's a fun place to stop & enjoy the atmosphere.
Consider a stay at the Stroppel Hotel in Midland. Miss Vicki enjoys tired, dirty DS riders!
http://www.southdakotamagazine.com/a-spa-at-midlandFour of us, riding off pavement to Alaska, will be on the TSDAT in early June. Hope to see you along the way.