For a traffic-free (and mostly human-free) alternative to Isola di Ortigia, there is a lovely crushed stone bike path reaching north from the city of Syracuse along the coast. Runners can pick up the trail at Piazza Cappuccini. The mostly waterfront path hits a sculpture park after about 1 mile, then continues all the way to Targia. It’s about 6.6 km one-way, but can be shortened to an out and back of any desired length. Can also be combined with the Isola di Ortigia route with a few extra km on Riviera Dionisio Il Grande.