While I agree some situations are unavoidable and should be explored for allowing cyclists, I still say a cyclist should generally not be on an interstate. I would rather put my legal efforts toward places that apply to all cyclists not just a few.
Additionally, there is no way it can be a 56 ADDITIONAL mile detour to go from Hannibal, MO to Pittsfield, IL (assuming you were traveling thru, not just crossing the river). Sometimes, your mode of travel dictates certain limitations. How come boats never have hills
I personally would not have traveled on US36 when there are better cyclists friendly roads that basically go the same direction, albiet with some extra mileage. I'm not putting you down, but I prefer to look at the landscape not at the traffic.
Finally, while you are an experienced cyclist, I would be worried about a novice who rides on it just because we have the right. Right or wrong doesn't matter if your are dead.
Again, just my two cents worth.
Happy trails and may the wind be at your back!