The most common transportation in the United States is the car. The road network well developed and covers the entire country. If you want to rent a car, it's not a problem, car rental is available from the age of 21, the cost of insurance depends on the age of the lease, the older the insurance is less. Road traffic regulations are binding, do not break traffic rules.
Taxis: call a taxi by phone is possible, well, or just get a taxi from the hotel or on the street, usually this is also no problem. Public transportation is everywhere, so it is also not a bad option.
There is no clear answer to the question what kind of convenient way to get around there, everyone defines it for himself.