One of the blogs I follow, "Creme de Memph" has assorted articles on the development of Memphis.
The second part in a series looking at Mud Island was just released. It goes into a little bit of detail describing the never-realized plans for a freeway connecting the ghost ramps at the end of the Hernando Desoto Bridge to the TN 300 spur, a Riverside Expressway (instead of Riverside Drive), and a couple of very early versions of a map I once had stuck to my bedroom wall illustrating the long-range plans of the Memphis/Shelby County freeway system: https://cremedememph.blogspot.com/2018/06/mud-island-history-2.html
Thanks for this.
This thread answers the question I asked yesterday on the "Re: I -40 Hernando Desoto Bridge at Memphis shutdown" thread: "Also, I have noticed that the eastbound off-ramp and the westbound on-ramp to and from Front Street have stub ramps: https://www.google.com/maps/@35.1529006,-90.0522629,473m/data=!3m1!1e3. Were those stub ramps to have gone to an unbuilt freeway in Memphis, such as an extension of TN 300 or an extension of Riverside Dr.?" Thanks.