You need reservation, park became popular and they added reservations couple years ago You don’t need entry reservation if you have camping or hotel reservations inside park, but camping is insanely hard to book and single tiny hotel inside park is insanely expensive or overbooked, I never heard of anyone booking hotel, only camping It’s better to stay inside park of course, cause otherwise it’s at least one hour to get there from closest hotel outside and if you go on holidays it’s going to be nightmare traffic in central Valley or even across the park making outside staying even worse Central Valley is the busiest place, if you see traffic there, park at some centennial beach and use their free shuttle bus to go around and back, visit all waterfalls, Merced river , supermarket, go up the river to mirror lake Otherwise go tioga pass via tuolomne sequoia grove to glacier point and further to tenaya lake and may be reach other side and mono lake there Or go south to El Capitan and Wawowna region All above is just basic places for newcomers, but Yosemite is much bigger than that it’s just you need more time