No vaccinations are required. A valid passport is required for entrance into the U.S. Visitor's Visas are issued upon arrival to most nationalities. There are a few domestic airlines operating within Alaska as well as bush planes which can be chartered privately. Bus is a relatively inexpensive way to travel within the State. The Alaska Railroad is scenic and enjoyable, but considerably more expensive.
Ferries are the main conveyance in the areas lacking roads.
The Anchorage International Airport is the major gateway for air arrivals. The Alaska Highway connects Alaska with the rest of the continent and it is possible to take a series of busses or, if you choose, drive. The Inside Passage is the main water way and ferries run between Bellingham, Washington and Juneau.