Lost in Random features six worlds, one for each side of the die. These include Onecroft, Two-Town, Threedom, Fourburg, Fivetropolis, and Sixtopia. There are also some areas between these worlds that you can explore such as the Valley of Dice.
Once you have traveled from one world to the next, you will be unable to return to these previous worlds. Each world is split into different areas on the map, and those that you can backtrack to are labeled.
Related: Can you save in Lost in Random
Since there is no way to return to another world, you will want to make sure you complete all quests, collect all cards, and collect all Storybook Pages in a world. Once in the world, open your map to see how many cards and Storybook Pages there are. You will have to be diligent to find them all, but it is worth doing if you like collectibles.
Main quests and side quests will also appear on the map, but some require you to discover them before they do. Collecting all the cards, Storybook Pages, and completing all quests will allow you to experience everything that Lost in Random has to offer. Plus, collecting all the cards expands your options in battle.
For more options on Lost in Random, check out Where to find the Storybook Pages in Onecroft in Lost in Random? and Is there a map in Lost in Random? on Pro Game Guides.