Get the guts out and remove the motors and the board
Hot glue the micro-switches to the buttons.
Mount the LCD on the cassette lid.
Wire the buttons
Solder the buttons to the main board
Wire the LCD
Ready for final mounting. Select a spot and dremel a slot for the SD card. Notice I built a small circuit to enable the rewind button.
Lotharek's board does not come with a "previous file" / "back" dedicated button.
However, the previous file (navigation in reverse order) can be accomplished by simultaneously pressing SHIFT+K4.
This "rewind option" can be implemented with the following circuit, which emulates the simultaneous press of SHIFT and K4:
It is made of two NPN transistors in parallel. Bases of the transistors have their respective current limiting resistors but then are joined together and connected to the "Rewind" key. One emitter goes to the Shift Key and the other emitter goes to K4 in the lotharek Board. As a result, a single press of the rewind key sends a SHIFT+K4 command to the board, producing the desired rewind effect.
SD card in place
Final product in production. Everything is battery powered