Hey, great thread here.
Sept 1st, my wife, my dad, and I are leaving Atl and riding to Seneca WI (just north of PDC). My wife and I did this ride 2 years ago and she mapped out the Great River Rd, but like you mentioned, a lot of that takes highways and stuff.
I'm thinking the MRT sounds like the perfect route to follow this time. However I noticed IL & Iowa aren't finished. For a bunch of IL, we could just jump over to the MO side and ride up that side. Are there parts of IL or IA mapped out yet?