I thought you might like to see her in that role.
Here are 14 minutes of that original production on The Ed Sullivan Shows. It's two segments edited together, and I suspect it's from two different broadcasts. (Ed introduces the premise of the show in the second clip, even though Dick Van Dyke has already done so before the first clip.)
In addition to being a good show, I think there's a pretty obvious reason Ed Sullivan liked Bye Bye Birdie and (much as he liked promoting Broadway musicals) particularly liked promoting this one. And if it's not obvious before seeing this first scene and song, it most certainly will be after.
And as you watch the second clip, keep in mind that not only was this the first substantive acting that Dick Van Dyke had ever done -- before then he'd had a nightclub act (usually with partners) and hosted TV or radio shows -- but more importantly, he'd never danced before. He was sure that that's why he'd never get cast, but director/ choreographer Gower Champion said not to worry, he'd teach him. Seeing Van Dyke, you'd think he'd been dancing for decades. And that he was made of rubber.
(You'll note that the setting of this famous song is different than how it was staged in the movie. I think they improved on the plot -- and casting -- and did a better job for the latter. In the film, he sings "Put On a Happy Face" to co-star Janet Leigh who thinks things in their life are getting out of control. On stage, he sings it to a couple of unknown, unnamed, nondescript young girls who are sad that Birdie is going into the Army. Charming as the scene is, it doesn't really advance the plot much, or deepen the character, other than showing him to be a nice guy, which we already know.)
But first, here's Susan Watson, Paul Lynde and cast. And it's worth mentioning that the actor who plays Conrad Birdie in this clip and original production is Dick Gautier, who later became better known to TV audiences as Hymie the Robot in Get Smart.