I made two steam generator cars from Intermountain 40ft AAR box cars. The kitbash required two box cars, new roof, new ends, and MT BX express trucks.
One was the power car for my Pacific Starlight Dinner Train.
The other I did in 1954 CN for Fredrick.
You say your kitbashing skills are nil, however this one wasn’t that bad. PM me if you want some assistance.
Craig.