68HC11 MCUs can be programmed very easily as they come with a built-in bootloader.
In the simplest form, you can even use DOS commands to copy the S19 to the serial port (after setting the COM parameters).
You just need to have the MODA/MODB pins in the correct state before powering up.
Also, JBug11 download | SourceForge.net works very well under Windows.
Hope this helps.