Well, I can do a reversal without too much trouble if that's required. A DPDT relay or perhaps electronically. I'm going to be wiring a small board for the custom lighting anyway, so I'll have a place for a few more components. The nice thing about this locomotive is there is tons of space inside, so I have room to get creative. The Cruise Commander will be in the locomotive, and the RailSounds Commander will be in the tender.
I might get by by just shorting the leads of the motor with the relay when I want to stop it, that will stop a freewheeling DC motor in a hurry.