The earlier you get to Taormina, the smaller the crowd. It just gets busier and busier after that.
I usually skip the theater not wanting to pay for admission. There could be a long line for tickets if not included.
Earlier this year I tried the app, GPSMyCity and Taormina is one of the cities include. Some of the app is free, but if you want the navigation part it costs extra. It did seem to work fine, but I already knew where most of the locations were.