Plane and Train
International flights connect to Zurich Airport, Geneva Airport, or Basel EuroAirport. From there take the intercity trains (IC) to Bern Station. Change to the ICs in the direction Thun, Interlaken, Brig, or Milano. Exit at Thun Station. The total travel time by train is roughly 1.5 to 2 hours. IC trains go every 30 min during day time.
Please check your schedule at http://www.sbb.ch/en/ the official Swiss railway website. Enter Zurich Airport, Geneva Airport, or Basel EuroAirport into the From field and Thun into the To field. You will also find prices and online shopping of train tickets there. Reservation of seats is not compulsory (and rarely used by passengers) in Switzerland. The price varies between 50 and 60 Swiss Francs for a one way ticket to Thun.
Thun is 20 min from Bern, the capital of Switzerland. On the highway follow the indications Thun/Interlaken. Exit at Thun. Parking is provided by the hotel.