I am a history buff to a degree. The "I" system in general bypasses that history. Many times I choose to do it the way my granddad had to, navigator with map in hand. Most of these roads have 18 wheelers on them so you should be ok with whatever rig you have. I do cheat some on this grand plan by using google maps, because it will tell me of construction or routes without traffic problems. The original plan is research and map in hand to make sure I don't miss the highlights. More fun to drive routes can be found on motorcycle roads.com, FieldTrips (app) lets you know of places you may otherwise miss out on.
Did you know US route 66 was almost completely replaced by I-40? Where I sit right now is a Richfield gas station on US 66 that was featured in Easy Rider. 25 miles from where I sit is the gateway to the grand canyon, Williams AZ, the last town on US 66 to be bypassed by I-40.
I do not lament on the loss of the route and enjoy a quick trip on the "I" system on occasion. Did you know the TV series route 66 was seldom if ever filmed on anything to do with route 66? What I am saying is across this country the "I" system has bypassed many points of interest we should seek out, to enrich our soles. The Fox Fire books about the history of families in the hill country of the east has a museum that would be a great shame to miss, almost like missing the grand canyon except it was real history written by school kids as an english teachers project to increase the kids desire to learn.
Oh! to answer your question I don't think there is a bad route and I am glad to hear you want to change up your travels.