Here is where you can find the mall, movie theater, restaurants and so on. Port Angeles is where the kids of Forks go when they want to shop and just hangout.
Seattle is where Victoria was growing her small army. It is also where the airport is located. Forks and La Push residents go there on weekends sometimes to get away.
Volterra is located in Italy. Its the city where the vampire royalty, the Volturi, live. They rarely leave the city, when they do it's to take care of trouble.