My next step is to create a custom case for the Pi 3b and front panel board. If all goes well, I will have a 3D printed case to hold both (rather than two separate boxes). 

One issue that has come up switching from the Raspberry Pi 3b to the 3b+ is the "RUN" header. On the Pi 3b, the second pin next to the RUN header is ground. The "Start" pushbutton of my interface uses these two pins.  On the Pi 3b+ the second pin next to the RUN pin IS NOT GROUND. It is the PEN pin and cannot be used with the Start pushbutton. Also, none of the pins on the POE connector have a ground pin. For the Raspberry Pi 3b+, connect the Start pushbutton between the RUN pin and one of the ground pins on the GPIO header. The most convenient pin is probably pin 39. The Raspberry Pi 4 has a slightly different pin configuration, but the instructions are the same. Connect the Start pushbutton between the RUN pin and a GPIO ground pin.