I'm starting on the build instructions...  though there will be LOTS of edits as the system takes shape.

The first assembly step is the control panels.  The rest of this cockpit can be scaled up and down a lot, but the heart of it are the buttons and switches that the kids will have their hands on!

Supplies for this part are - 

Panel material.  I used acrylic but you could splurge and go for aluminum... or you could skimp and go with masonite.  My big box hardware store has 4X8 panels of masonite that's finished white and glossy on one side for use on bathroom walls and similar environments, and this would make a pretty nice feeling panel at $14.00 per whole sheet!    I may use some of this for the interior walls of the simulator to make it feel clean and shiny without a ton of money spent.

Buttons and switches - I used 38 basic momentary buttons, 7 lighted momentary buttons (rcs, sas, lights, gear, brakes, staging, and abort) and 5 spdt switches (white lights, blue running lights, cabin fans, master power, and communications.)  I also used a really nice $15.00 8-way microswitch joystick from Amazon for the linear RCS.  I may buy another one and replace the attitude control buttons with it!

I'll post my layouts for the panels, but feel free to do your own thing designing them if you'd rather.   I organized my controls into 4 panels and built them individually so I could get my hands on them and make sure I liked the arrangement before the whole cockpit was built.  You could absolutely build the whole control panel as one unit if you're confident like that.   I'm putting an "Engineering Panel" on the far right, with controls for all shipboard systems.  In the middle will go attitude control and autopilot where all three kids could reach them.  On the far left I'm putting the linear RCS controls where they'll mostly be used by the pilot for docking.

I cut my panels out of clear acrylic, then I drilled and dremeled all of the holes for the buttons and switches.  Sanded the edges of the holes and table saw cuts , drilled mounting holes, and then painted the backside.

When your paint is dry, handle the labels.  I  printed 'repositionable window decals' from Staples with the panel markings, stuck them on, then x-acto knifed out the holes.    They look good... but not as good as the panels looked before the labels.  I may revisit labeling.  

Mount all of the buttons and switches.  How you go about this will depend on what you made the panels out of.

Solder umbilicals to the back of every panel.  One side of all of the buttons and switches will get tied together - this 'bus' will be hooked to ground.  The other side of each button gets it's own wire - these will be hooked to the io pins of the launchpad to serve as the inputs.  I used 8 conductor ethernet cable I had laying around for this... so I've got 9 cables running from my panels.  Label them as to where they go, especially if the launchpad and the buttons are going to be far enough apart that it will be a pain to look over and see what cable-3, conductor seven is hooked to!