I'm glad to see that someone else mentioned "Say Hello to Harvey". I'd forgotten all about it. I also have no idea what the book was like (except that they updated it and had it happen in the present, late 1970's at any rate). I half of the score is terrific and half of it is pure crap. It does have a terrific, show-stopper comedy song for the sister called "Lousy Life" that she sings upon getting home after being mistaked for a patient at the sanitarium. Possibly the song isn't as terrific as I think it is, it could just be that Patricia Routledge did a killer job with it. I'd be interested (if I ever became a millionaire) in reviving it, if I could get Leslie Bricusse to re-write half of it. (And, from what I heard about what went on during "Dr. Doolittle", he wouldn't want to re-write.) He went on to re-write the song and give it to the character of Sherlock Holmes' housekeeper in this musical "Sherlock Holmes".
I don't know how well "Reefer Madness" would do on Broadway. Yes, it would have a young fan base, but the older playgoer might not like it. I saw a first-rate, college production of it and it felt very long. That's a problem with doing a musical version of a cult classic. Every little moment ("Why isn't your baby crying?") gets turned into a song, which leads to a very long evening. It would have done better as a ninety minute, one act.
"A coherent existance after so many years of muddle" - Desiree' Armfelt, A Little Night Music
"Life keeps happening everyday, Say Yes" - 70, Girls, 70
"Life is what you do while you're waiting to die" - Zorba