Yep, the willow tree was amazing. At least, in my memory, it was a willow, like the one on the cover of the Greenwillow album. The rest of the scenery was pretty good, too. I remember small town building facades.
And there were protests against James Coco playing a Chinese servant, which I know has been mentioned here. And Ken Kercheval did chin-ups on the tree, maybe while singing the title song -- which always reminded me of "There's A Small Hotel." And the costumes and lighting were suitably evocative. But the show and the score, well, unfortunately, not as memorable.
But I could be entirely wrong. The forgotten score could be a gem, and it's just waiting to be discovered. But, at the time, I don't think anyone recorded even a piece of it.