The controls are made accessible trough the case vents. Keeping the front case intact, and in the spirits of the legacy button. It also make them barely visible.

Some people are using the floppy drive hole for that purpose, but it looks weird to me.

By the way, if you have original idea on what to do with the floppy drive hole, I like to hear from you!

Printing

STL should be printed with their default orientation.

On the screen control holder, no support is needed if you enable Make overhangs printable option (for eg on orca slicer).

I have used 2 small M1.7x5 screw for attaching the keyboard to its support. The hole in the model are designed for direct usage.

Notes:

The button are only inserted in the vents, and it's the keyboard pressure that keep them in place. They can move a bit… but it works good enough.

• Install first the button plate into the vents: look roughly where it should fit by positioning the other part above and looking where the screws need to be. The plate goes under the metal chassis at this place
• Then install the second part: it is easier to pre-position the screw inside this part, or at least one screw, and slip in the other by untying it.

Then test the buttons, they should click, meaning that everything is ok.

For better look, I paint them with light grey, with the same paint I used for the screen bezel.

For passing the keyboard cable, they are 2 options:

• using the chassis hole just above, but I tried to avoid that, to allow attach futur things (but what ?) in place of the floppy disk
• by passing on the side between the frame and the chassis, a bit more difficult, but cleaner in my opinion. 

My notes on the complete project can be found here