Get a train ticket at Long Bien Trainstation ,Hanoi or take a bus from Luong Yen Busstation,Hanoi (45000 Dong)
Taxis or private car from Hanoi to hai phong cost about 80 USD one-way.
-Down at the port(City Center,Ben Binh Street) depart ferries to Cat Ba Island (up to 100'000 Dong)
-Visit "Dosoen" about 20 km south of Haiphong ,just take a local bus (10000 Dong)
Has the biggest port in Asia