Kid Andrew Cody and Julie Sparrow is amateurish in the best sense of the word - it's enthusiastic and idiosyncratic and Curtis takes the narrative wherever he's interested in going - perhaps ad libbing as he liked to as an actor. I read it in one night when I was 15 or 16, and again in my 20s much more slowly and carefully, and both times I enjoyed its pace and gusto and poignant humanity. The opening line is "The 20th Century Ltd pulled in to the station.", and I thought this was symbolic - the 20th Century Ltd is actually a train that went between NY and LA. The sentences in the book are short and snappy and tight and witty, and it starts fast and stays fast, and keeps a clear line of progress even with its discursiveness.
He was also a beautiful chat-show guest, usually as an engaging, funny storyteller. On Aspel in 1984 he upstaged both Jackie Collins and Pamela Stephenson, which I would guess is not as easy as he made it look.