Visited Carson City with my son in 2013,
and was much impressed by the McKeen and everything else...
Great people there, one of the guides went all out with his tour and my questions.
My first thought was also "wow, the wrong engine",
but I then had to agree that the cat engine was a smart idea...
We faced similar decisions with prewar trucks several times,
and usually ended up with a cobbled together mess that broke down on every trip.
Didn't take pics of #22 as I was aware it is well documented online.
I attach two pics of the poor donor McKeen
(which was rebuilt several times by the Chicago Great Western,
and ended as a switcher somewhere in the Midwest)
Which has given parts to rebuild #22,
and the Hall Scott Motor that is stored behind the carhouse.