Isola Bella is easy to reach if you are visiting other destinations in Lombardy or also Switzerland. Regular trains operated by Trenitalia connect Milan to Arona and Stresa, both located directly on Lake Maggiore. From either Arona or Stresa you can pick up the Lake Maggiore Ferry Service and travel to Isola Bella. Ferries return back from Isola Bella until early evening (6:30pm on the summer schedule) and you can buy different tickets based on whether you just wish to visit Isola Bella or the other islands of the lake, including Isola Superiore and Isola Madre.
The train from Milan takes only about an hour and runs frequently. The ferry service is quickest from nearby Stressa (only about 10 minutes), however the hour-long ride from Arona is quite relaxing and a wonderful chance to see some of the scenery along Lake Maggiore's shoreline.
Once you arrive at Isola Bella, go to the ticket office where you can purchase admissions to the Garden and the Palazzo. Last admission times are between 5-5:30 pm and plan on at least 90 minutes to 2 hours to explore them all. In the Palazzo you can see such wonderful sites as the Ballroom, Napoleon's Room, numerous Grottoes, the Tapestry Gallery, the Queen's Room, and much more. Paths will guide you through the palace and then you will emerge in the gardens where you can explore multiple levels of greenery, flowers, sculpture, a tropical greenhouse and aviary.