The Galapagos Islands was the place where I enjoyed more watching animals on their environment, protected from human intervention! Most of the people visit these islands on organised cruises but it’s not difficult to organise a trip yourself.
There are three inhabited islands. I recommend flying to San Cristóbal, then visiting Santa Cruz and Isabela. You will have to return to Santa Cruz for your return flight. Three or four days on each island are enough. Food, accommodation and activities are expensive compared to Latin American average prices, so it’s better to speed up your visit to Galápagos and save your budget to visit Ecuador or Peru.