So after some more testing and reaching out to an old friend I was able to get my hands on a functioning Lionel Railsounds 4 powered board for essentially nothing. At this point I believe all I need is the ERR Cruise Commander.
However one thing I did not consider was the wire connections. I know how to re-pin connectors from work, but not sure what Lionel used for connections. They look like some kind of JST connectors? I have gone back through posts from @gunrunnerjohn regarding these but just trying to make sure before pulling the trigger on the ERR Cruise Commander. Still hard to believe EOB was making the motor sound that bad.