I was probably most worried about the sim going into the interview, mainly because I'd hadn't done any serious instrument flying in about a year, and most of that was in a 172. And it didn't help knowing that it is the number 1 killer.

That said, it really wasn't that hard. You take off, get some vectors, and fly an approach. No failures or anything tricky. They give you more than ample time to brief yourself on the approach, and they even have a card posted in the sim which has the appropriate speeds and profile for the aircraft (which is supposed to be a Navajo if you get the ATC).

So I'd say prepare, yes, but don't fret. I'm not sure you absolutely need practice in the Frasca, or any specific sim, but just be capable of doing some really basic instrument procedures at 160 kts. or so. They offered me the job, so it can't be that hard.