The easiest question you ask is
How authentic can a person get?
The answer is...almost totally. Every switch, knob, handle or guage in the plane can probably be made to function as part of the sim. The vast majority certainly can be functional. The original guages could even be converted over to work based on sim outputs.
The cost would be prohibitive though...even if you did most of the work yourselves rather than buying pre-configured components. Figure on somewhere in the $15,000+ range for all of that.
At the bottom end...it depends on how much of the converting you can accomplish yourselves. The computer to run FS and the flight control conversions are going to be the expensive bits. I would recommend a good gaming computer as the base (expensive but the increased visual quality and framerate are worth it). For the controls...Phidgets (
http://www.phidgetsusa.com). The InterfaceKit 8/8/8 gives you the needed functionality to add your throttles (2), primary flight controls (aileron, elevator and rudder,3), flaps (1), differential wheel brakes (2)...8 analog inputs (and more than enough realism). You also have the option of adding 8 digital outputs and 8 digital inputs (switches or the like).
That would make a very nice starter configuration for the 'pit...and leave it easily expandable for later (additional Phidgets).
I'm sure you are already aware...but many places will give you a deal on prices for a Museum. Hit up some of the companies (politely) and they may toss you some good stuff or at least shave the profit margin a bit.
Good luck on your project and feel free to ask any question that pops into your head...that's what forums like this are all about.
