Depending on how long your trip is, do you really want to leave the HongKong area? You can explore the more rural areas and take the hydrofoil to Macao for a day or two. It probably will require a visa, but you could go by land to nearby places in PRC. There is a well organized bus system, or your hotel can book a car and driver for you. HongKong itself is fascinating and deserves time for exploration.