From Island Cres there is bus to Lucerne via Rijeka, from beginning of July to Mid August there is daily bus departures, rest of the year, 3-4 weekly departures. From Cres bus station you first take a bus to Rijeka, this takes about 2.5 hours including the ferry trips. At the Rijeka bus station you can then change to the bus towards Lucerne, ticket prices and departure info for that route you can see below. Total bus travel time is about 14 hours.