Our "recommended number of days" are here as a guide to help you plan your trip. The numbers of days you see are only a suggestion and are for reference if you are planning a trip with a limited number of days and also planning to experience these parks for the first time. Please keep in mind that we are strong believers that it can take many more days than the recommended number of days just to explore a park. For example, we recommend 3 days for Yellowstone National Park for a first trip. However, this is a large park and after countless visits to Yellowstone, none of us at US-Parks.com can say we have fully experienced the park yet. With so many trails to choose from (easy to hard, including backcountry), this can take a long time! So keep in mind when you are using these numbers to help plan your trip that they are here merely as a guide for a first time visit. Once you have experienced the park for the first time, you will get an idea what appeals most to you and where to focus your time for your next visit back to any of the parks.