Good news this morning. Per the excellent guidance, I found an "anomaly" (either me or the original install are guilty- your call) and made sure of the connection from pin 24 on the R2LC to the J4 pin 1 on the CCM. All works according to plan. This is a new CCM board and it appears the buffering is ok, but I plan to contact GRJ for future CYA needs.
I do have one odd thing going on. I have a battery installed and when I shut down (zero volts to track and TMCC off), the sounds on the locomotive continue until I lift it off the "dead" track. Am I in the twilight zone or bermuda triangle here?
For anyone who finds this thread in the future, here is the pin out for the R2LC.