I agree. I would rather see them in Prisoner of Second Avenue. I think one set of charters from them would make a more satisfying evening.
I just watched the trailer, linked below. I don't think I could tolerate three acts of them acting goofy in period costumes with the audience roaring with laughter at the slightest thing. I imagine that's the way it will go.
Like many, I am fond of SJP because of Sex and the City. I've never thought she was great on stage the few times that I've seen her.