I have the novelization which features the original ending. It's worth picking up. I bought it on Amazon for $1.00.
Some interesting interviews marking the 30th anniversary of the movie. Director Walton says the original ending was filmed and screened but Paramount felt the movie was too long and that the party sequence after the Muffy/Buffy reveal was the better high note to go out on. The tag with Muffy, Nan and the jack-in-the-box was filmed months later. A third alternate ending with a bonfire was also filmed. Frustratingly, there's no discussion of whether any cut footage still exists. http://dailydead.com/april-fools-day/ A couple other articles with quotes from a number of cast members. Interesting reads, though I question the authenticity of some of the quotes. (Every single actor interviewed is gushy and verbose in ways that just don't quite ring true, IMO. Walton must have some great dirt on all of them, they way they all passionately kiss his ass sing his praises.) http://dailydead.com/april-fools-day-30-cast-discusses-working-fred-walton-moments-missed/ http://dailydead.com/april-fools-day-30-cast-reflects-cult-classic-horror-comedy/ And while there's no discussion of April Fool's Day, you can see what Deborah Goodrich and Clayton Rohner look like now at this 30th anniversary screening of Just One of the Guys from 2015.
The screenplay has a different ending from the novelization, although both endings start off with them heading back to scare Muffy.
