Sullyman26:
Well, out of curiosity, I Googled your Williams Dash 9 engine and an Amtrak one came up on eBay with some pretty good photos. That's a pretty big engine with pretty big motors. Looking at the cab photo, the visible forward motor looks like it almost reaches all the way over to the cab windows without much wiggle room to shoe-horn in an engineer figure. Pretty tight. So, I can understand your reasoning if you want to install a cab interior.
I'm sure you'll use your best judgment with your decision and good luck. 😉