That actually sounds inviting. Smoke from the caboose from the wood stove - very cool. Might be able to pull that off in HO ? Got me thinking.
Lots of open room in them.

Someday when my wife lets me retire I will have that thing called "TIME"

It appears Rapido has different configurations for different models, as based on this thread on MRH the 44-tonner Mo'Power was able to be used with non-ESU products, but for the D10 there is no fix (https://forum.mrhmag.com/post/rapido-h1644-decoder-question-13640397).

(MRH) NorthWoods Bill
On the Rapido 44tonner enabling FX6 allows a Tsunami to work with the Rapido Mo Power. Tried the same thing on the H16-44's with no love. On the Rapido D10's there is no fix.

In my ScaleTrains motherboard project, I have spent the bulk of my time trying to figure out the lighting situation, I haven't spent much time with the power pack to see if I can get it to work with the LM. Once I have time, I will be tearing apart a spare motherboard to create an accurate diagram and that should give us an idea on what is actually happening (With the lights and the powerpack).

Looks like you will be dealing with a 21-pin install and if the Mo'Power is like the keepalive ScaleTrains uses (Whatever term ESU uses), it has the capability to be turned on or off. It also may not be on the same pins at where RailPro would like it to be.

I'm in the middle of trying to understand a ST motherboard to understand the lighting and the powerpack, and how to get it to work with Railpro.

For example - Directional Lighting - I have a GP7 that has marker lights and it would be cool if when Directional Lighting was turned on, the marker lights to the rear would also turn on.

No insight on Rapido, but I know that TCS keep-alives did not really work with RP. Much better to go with the PBs, as I learned.