Hi, Oz,
Mr. Kermit would be about 5 feet eight inches tall, with plenty of semi-curly dark hair -- he's probably a little shaggy, needing a haircut, and a face that is not used to smiling -- although he gets better and smilier as the story goes on.
His clothing is ordinary dull -- dark pants and tweed jacket, maybe a tie -- your choice.
Have fun with it! -----Gordon Korman-----