Everybody knows she gets liquidated in the Oz sequence, but that's not Kansas. For all we know, she might have moved to Topeka. Wouldn't it have been nice if they have given the audience some indication of what happened to her in the real world? Having one of the characters say "I hear they found Gulch's bicycle hanging from a weather vane" would have provided some closure. Or, perhaps, "I hear the Gulch farm is nothing but matchsticks." But no, she just disappears.
For all we know she might have moved to New York and taken up acting. Can't you just picture her traveling the country in the road company of "A little Night Music?"
It would be nice to think that maybe her heart had softened in her senior years, that perhaps she might have become less naughty and more nice. Sadly, I suspect this is going to remain one of those unanswered mysteries. We will most likely never know what ever happened to Elvira Gulch, or where she is now.