There are many ways to do a bike tour. Many people like to sign up to one of the many organized bike tours that are available. These vary in the services provided. Some do just about everything for you including transporting your gear, arranging accomodations, setting up camp, cooking meals, etc. Others cater to self supported riders and just provide routes, tour leaders, advice, and such.
There are cross state rides like the OK Freewheel (www.okfreewheel,com
) that provide routes, arrange camping locations, and transport your bags that are very reasonably priced.
Many people opt to forego organized tours and strike out on their own. There's no reason you can't pick a destination, plan a route, load up the bike, and go. It certainly helps to be familiar with the roads between you and the destination. If you plan to do a long cross country tour, look into adventurecycling.org for well researched route maps that might interest you.
Some people pack camping gear and sleep outside most of time to save money and enjoy the great outdoors. Others leave the tent and campstove at home and spend each night in a motel. It's all in what you want to do.