If you are looking for a region which gives you a good variety of places to visit, then I think that Veneto is the best choice: you have the sea (the beaches on the Adriatic Sea are much safer than the ones on the Tyrrhenian Sea, for example at Caorle there is a little basin where the water is always less than 1 meter deep); you have the mountains (Cortina, Sappada, Alleghe, plenty of great places