Hualien/Taroko Gorge, bus or taxi or van rental for 5pax?

we're a family of 5 are planning to visit Hualien &Taroko Gorge around Dec 26 2D1N. Is it better to book private car/van to move around or can we easily get taxi or van upon arrival at Train station. If Taxi wondering how to fit 5 adult? or to take bus ? or if van, how much and where to get reliable transport van?