Be forewarned: Traffic in Naples may be extremely heavy, just to compare: very similiar to New York's. Traffic around the train station is nuts. Before attempting to cross the street, observe the locals. The idea is to spot a gap in the traffic and start across and hopefully people will stop.
There are several ways to see Naples and the surrounding area. These include by taxi, train/subway, bus. Taxis are the quickest way to see Naples, but also the most expensive. Before getting into a taxi, make sure it is licensed. Licensed taxis will have a city crest on the door and a taxi number. Also, make sure it has a meter. By law, licensed taxis must display a list of pre-agreed fares in a number of languages (Italian, English, French, German, Spanish). Check the presence of such fares and agree to them before starting the journey. You will be surprised how easily you can get around by foot, too. Interesting spots are almost on every corner and most distances – especially in the (historic) centre – are small and can easily be walked in a matter of minutes..