The new "JIM" will be released with 1.28C so at least you can set up single missions and fly with the 1.28C exe with access to all of its features. This is because 1.28C contains the "JIM" code (without the need for a different exe). It will just be a matter of launching EAW, ignoring the garbled mainscreen and clicking Ctrl-Q to start a quick mission.
At the end a couple of clicks on "Esc" will get you out of the debriefing screen.
This whole routine only runs if the user selects an instant mission (or presses Ctrl-Q) and there is a "JIM" folder with "SingMiss.mpf" file (made by the JIM utility) in it. Otherwise the "normal" instant mission routine runs.
Check the OAW128V13 thread for pictures.

Jel