Wow! I've always had reservations about Grace Kelly and been astonished by the rapturous adoration of her fans, but I never especially disliked her. I now think she was a pretty good actress, better than is commonly recognized but I agree with you about her looks.
When Grace Kelly drives Frank Sinatra around the area, showing him the grand houses, some of which are too expensive to maintain, is very much an old money sequence. Bing Crosby was not re-channelling Cary Grant and Frank Sinatra was not trying to be like James Stewart.