Get stereotyped?The only one I know of ,who played Un-"Professor"roles,was Russell Johnson.He played Don's friend,a pilot on "That Girl",a villain on ABC's "The Big Valley",a doctor on "Marcus Welby MD",DA Grant on the first 2-seasons of ABC's "Owen Marshall,Counselor at Law",and the murderer who drank pop and ate peanuts,on NBC's "Ironside".This was before "Rescue from Gilligan's Island".And whatever happened to the late Jim Backus?Did he play any other non "Mr.Howell" roles after the series ended?

Jim Backus certainly wasn't typecast, he had a long list of credits before G.I. and afterwards. He certainly wasn't without work even though it included reprising his Thurston Howell role on occasion.