It is regrettable that the need to follow an exact routing
takes precedence over the quality of the cycling experience, itself.
With historic routes like this we have to walk a line between remaining true to the route as prescribed through history while creating an experience a traveling cyclist would enjoy. What we've learned from creating historic routes is that the people who are interested in the history tend to want to stay as close to it as possible, no matter what. Safety, closely followed by services, is usually the biggest factor we consider when we decide to deviate from that. I agree, your suggested routing might feel a bit more like traveling in the 1930's. It's not clear to me that's what people are looking for by retracing Route 66. Also, your alternative has unpaved sections. According to our latest survey, our membership is still mostly interested in riding on pavement.
None of this means we won't consider including mapped or suggested alternates in the final product. The Lewis & Clark Bicycle Trail route has multiple alternates and spurs in order to preserve as much of the historic information as we could. These factors will all be considered when the route is actually laid out.