The length of your stay should depend on the type of itinerary you want to build and the size of the park you are visiting. There are many itineraries for Yosemite online that involve staying three to five days, but you could certainly spend much longer or shorter periods of time. Worth noting: Some smaller parks and historic sites may not be open every day. Larger parks may close due to weather events. Always check in with a park (either online or by calling) beforehand.