[hbens]

Jim,

Although I have not installed a mini in place of the SCS units, I have had detailed conversations with those who have.

There are two modifications to your approach that you may want to consider. One, use this opportunity to snake one or two additional elephant trunks into the front compartment. Two, install some sort of manual damper in order to balance air flow to the rear plenum and front plenum. Otherwise air will follow path of least resistance which may not cool the coach evenly from front to rear.

Exactly what I was thinking but unable to come up with the correct jargon for it. 
Sufficient airflow has been a thorn I have had to overcome.