A Matter of Personal Choice
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Obviously, the 'best' route is the one that works best for you. But if I were looking to make this drive, and had two full days to do it in, then I'd pretty much opt for choice 4, for the sole reason that it best meets your criterion of offering the greatest variety. Not only will it take you through farmland and along rivers, but it is the only route that will give you some hill country, the Ozarks. Of course, if this is a round trip or you have more than a couple of days for the one-way drive, you could either take different routes out and back or add a few 'detours' to include some of the many sites that won't fall exactly on your chosen route.
AZBuck