I know about the 200 and the 300, but not the 250... Can you tell us more about the console? Could it be the GSX or LBX with 250 Channels? Tell us more and we can help!
I don't believe one exists or at least, to my knowledge Strand has not released one. I would imagine that they figure that is a lower end desk and it would not be worth the time that it would take to package that software into an off-line editor. By that I mean - there would not be that much demand for it (i.e. they haven't sold as many, or whatever)
You might email their tech support. Sometimes the Tech support technicians have little bits of software that the general public does not and that might be one of them. I know I have had various little pieces of Strand tech software in the past that I was not allowed to give out to the general public....
If it is, in fact, a Hog 250, I'm pretty sure that no offline editor exists. My old university had one of those, and I never found an editor...I even tried asking tech support. The only thing they gave me was another copy of the world's worst-written operator's manual...which I'm sure you've discovered already. The most unfortunate thing about that board is that it's so out of date, they don't even really offer much support for it (if any at all, now) when--not if, but when--something goes wrong. You're best bet is just to talk to people who have been forced to use it and have figured out its quirks.
The Jands Hog 250 runs the wholehog II OS I believe. You should be able to offline edit your show on HogII PC, save it onto a floppy and load it into the Jands Hog. Check out http://www.flyingpig.com/support/Wholehog2Support.shtml