westondc,
US-81 is a nice road, kinda straight and boring, but its in good shape. A one problem I can see is 81 is four lane from Nebraska to just north of Salina. It may not be a problem, just wanted to let you know.
As far as Old 40 Hwy, I have traveled that several times to Western Kansas. I like it better than I-70, no traffic, but it takes me to the same place. There are a few questionable stretches, but totaly ridable.
The motorcycle museum in Marquette is a MUST SEE ! Its pretty strong on the racing stuff, but the Stan Engdahl, the original curator of the museum raced bikes back in the day. unfortunatley, He passed away a few years back. He was a true wealth of knowledge, and a super nice guy
Not being pushy, but there is no fee to get in. They do have a donation jar as you come in, so feel free to contribute what you feel its worth. Trust me, its worth it.
Oh yeah, I have a good friend by the name of Todd Otto in Lincoln. He owns a body and performance shop called Otto Body on 56th st. He built a prototype 2010 TransAm out of a Camaro.
Anyhow, I digress.
Let me know when you guys head out, I'll try to meet up somewhere. Cant guarantee it, cause sometimes life gets in the way, ya know ? Let me know if you need anything else. I work for KDOT and travel the entire state so I have a fairly solid knowledge of the roads and routes in Kansas.
Thanks,
Dave