The 1,964-guest Oosterdam is the second ship in Holland America Line's Vista class, which set a more contemporary tone for what was to come over the next two decades. Still, the crowd on board remains solidly age 55-plus and the vibe is hardly a party scene — although a 2018 refurbishment added nightlife venues Billboard Onboard and Rolling Stone Lounge, which are quite popular and often rollicking. Oosterdam has just two specialty restaurants in addition to its main dining room, but the ship’s casual eateries — including the gourmet burgers and hot dogs at Dive-In — keep the culinary options approachable and fun.