I'm sorry to say that I understand exactly why Pinkwater's publisher reacted this way. You can only write so many novels chock-full of chaotic, random & unrelated events that finish up with a big party attended by all the book's characters before it grows incredibly stale.
I like Pinkwater. And I like many of his books - The Neddiad & The Yggyssey included. However, Cat-Whiskered Girl & Bushman seemed... unfinished. Not in a way that made you long for more - but in that unsatisfying 'why didn't he resolve the goddamn story' way that smacked of 'Holy shit! I've painted myself into this corner... how am I gonna get out of... PAR-TAAAY!!!!'