Darwin's voyage around the world took a little less than 5 years. When he got back to England, he had the raw materials, journals and specimens, that he needed to have in order to put forth his theory of evolution. But it took him 25 years to publish, and then only because he learned that Alfred Russell Wallace had come up with essentisally the same idea, and he couldn't let all of his work go unrecognized. The attachment here traces the route of Darwin around the world. For an excellent website about the journey from England to the Beagle's entry into the Pacific Ocean, I highly recommend About Darwin.com Information for the first part of the journey comes directly from there. Another excellent site that I used is Darwin Day Celebration. And of course I highly recommend, seconding jumble's recommendation The Voyage of the Beagle by Darwin himself. It's a very good read, not at all slow-moving like Origin.

Image from 1890 edition of Charles Darwin's Journal of Researches into the
Geology and Natural History of the Various Countries Visited by H.M.S. Beagle.