ottohlc
I can help you with dos, I was one of the first users in good old recalbox-times. Most Dos games run pretty well with the dosbox emulator, all Keens 1-6, Quake and Duke Nukem I, II,3D, Crusader No Remorse, no Regret (always my favorite dos games) Monkey Island1,2, Little Big adventure 1,2, and so on. Without forgetting the 3D Pro Pinball's. And all this games run already on the PI3, so I expect that they will also run on your PC.
To begin, you must create a folder under /share/roms/dos with your choosen filename and the extension ".pc" .
All names should be max. up to 8 letters and best all small letters, as the x86 version make a difference between small and capitals, so more easy.
In this folder you copy your game files. and the global file dosbox.conf that you rename dosbox.cfg. Because the emulator takes only a local configuration file, when it has the extension ".cfg".
This is important because in the local dosbox.cfg you adress a keymapper file specific to this game and you will mostly need an adapted keymapper file. Best to take same name as for the folder, the extension is ".map" and you have a line in dosbox.cfg at the beginning to define it. The original dosbox.conf you find under /system/configs/dosbox/dosbox.conf
For normal games, nothing else to do, but for games with control of a present cd, there is a section to load virtual images. (cue+bin)
And finally you must create a file dosbox.bat where you have in the simplest case inside nothing else as myprogram.com (or .exe)
Concerning the keymapper file (if you use a joystick configuration or gamepad), you must press after start of the game Ctrl+F1 to call the keymapper. After some time you will also be able to edit the .map file manually.
All special keys are here : https://www.dosbox.com/DOSBoxManual.html#SpecialKeys