One of the finishing touches I wanted on this project is to make the Raspberry Pi boot directly into the Sol-20 emulator on startup. 

I created an autostart folder on my Pi and switched to that folder.

mkdir /home/pi/.config/autostart
cd /home/pi/.config/autostart

Into the autostart folder just created I added the following two files.

runSol-20

cd /home/pi/Sol-20
/usr/bin/python3 main.py

Sol-20.desktop

[Desktop Entry]
Type=Application Name=Sol-20
Exec=/home/pi/.config/autostart/runSol-20 

In addition the runSol-20 file must be made executable with the following command:

sudo chmod 777 runSol-20

Now if you reboot the system, you should briefly see the desktop appear, and shortly after Sol-20 emulator will load.