It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle. — AmericannovelistErnest Hemingway
One of the main differences between road bikes and ordinary mountain bikes, is that road bikes use thinner tires so they can run at higher speeds. There is far less friction because of the tires, so the rider does not have to put in so much effort to reach maximum speed. Road bikes set up the rider in a way where they are lower to the ground. The handlebars also differ because they are curved to provide more energy.
OK - You've picked out your bike - now it's time for a road trip!