Flight
The closest airport is Rome, Italy (1hr by car-1.5hrs by train) to Virterbo, Italy. You can also fly into Florence, Italy (2.5 hrs. by car 3 hrs. by train) to Viterbo, Italy. Viterbo, Italy is about a 20 minutes bus or taxi ride to Celleno, Italy and the closest train station. Please note: for better flight rates look to flying into other cities in Europe, as you can usually find cheap flights from country to country once overseas. I would also check flights into London, Paris, Germany etc. Sometimes you can get flights from one city into Rome sometimes for as little as $80-$100ish. Some low budget airlines in Europe are: EasyJet, Ryan Air (can have delays), Air Lingus, Wizz Air, Euro Wings, Norwegian, BLUE Air, Iberia Air, Air Baltic, & Iceland Air. Also, look for flights on places like Skyscanner, Hopper, & Expedia.
Train
Other train lines you can book through: https://www.omio.com https://www.rome2rio.com The train station you will travel to from Rome or Florence will Viterbo, Italy. One thing to note if you buy your ticket through the kiosk make sure you get your ticket stamped with the time and date. (Otherwise you can get a fine) In our experience if you buy the ticket through the ticketing agent they already mark your ticket.
Hotel
There are plenty of surrounding towns and cities that are not far from the villa in Celleno. I would suggest Viterbo, Italy. Viterbo (20 minutes by car) is where the train station from Rome and Florence will stop. You will have more options for hotel. Also, keep in mind looking up Airbnb options too. My favorite hotel is listed above. Viterbo Hotels: -PALAZZO UBERTINI Urban Suites -Best Western Hotel Viterbo -Hotel Salus Terme - Adults Only