It would be amazing if someone could take the GOG port, and update it with a mod so that it plays keen 6 and dreams included...hmmm...

If you have the other two games, you can add them into their own folder and modify the dosboxKeen_single.conf
Can't post files here, otherwise I would share mine. And too lazy to get an online sharing account.

Note: if you verify or reinstall this will be overwritten with the original conf file and will have to redo this.
Change and add things like:

ECHO º 3) Episode 3: Keen Must Die! º
ECHO º ------------------------------------------- º
ECHO ÈÍÍÍÍÍÍÍÍÍÍÍÍ&Iacut e;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&Iac ute;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&I acute;ÍÍÍͼ
ECHO ÉÍÍÍÍÍÍÍÍÍÍÍÍ&Iacut e;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&Iac ute;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&I acute;ÍÍÍÍ»
ECHO º 7) Keen Dreams º
ECHO ÈÍÍÍÍÍÍÍÍÍÍÍÍ&Iacut e;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&Iac ute;ÍÍÍÍÍÍÍÍÍÍÍÍÍ&I acute;ÍÍÍͼ
ECHO ÉÍÍÍÍÍÍÍÍÍÍÍ&I acute;ÍÍÍÍÍÍÍÍÍÍÍÍÍ ÍÍÍÍÍÍÍÍÍÍÍÍÍ&Iacut e;ÍÍÍÍÍÍ»
ECHO º ------------------------------------------- º
ECHO º Commander Keen in Goodbye Galaxy! º
ECHO º ------------------------------------------- º
ECHO º 4) Episode 4: Secret of the Oracle º
ECHO º 5) Episode 5: The Armageddon Machine º
ECHO º 6) Episode 6: Aliens Ate My Babysitter! º
ECHO º ------------------------------------------- º
ECHO º 8) Exit program º
ECHO º ------------------------------------------- º

choice /c12345678 /s Which program do you want to run? [1-8]: /n
if errorlevel 8 goto exit
if errorlevel 7 goto kdreams
if errorlevel 6 goto keen6
if errorlevel 5 goto keen5

:keen6
cd KEEN6
cls
KEEN6
goto exit

:KDREAMS
cd KDREAMS
cls
KDREAMS
goto exit