TWENTY years ago the Playhouse closed and now it is open again. April is a month of awakening and the flowers and trees are doing their part. The fountain in the front patio is running again and people have been working to get everything right for the opening. Years ago I was one of those helpers. We got the scenery and settings in order and costumes finished just in time. Sometimes rehearsals went on all night. I am doing other things now, but the pull has been very strong to be one of the crew. It began when I was in a movie as a child, then in high school, and finally as a mother of teen-agers, working for tickets on Saturday afternoons when we could all go to see the plays.