Half Dome (Yosemite National Park) is a must do. Depending on the trail you choose and where you park, plan on hiking 15-17 miles. It took us 11 hours roundtrip, including breaks. The total elevation change is 4,000 ft and the peak is just under 9,000 ft.
What to pack:
Water: There is only 1 refill station about 2 miles in. For reference I brought 3L of water. Bring an insulted backpack and put ice in your water bladder. Electrolytes: You can either get tablets/powder to add to water, gels, electrolyte drinks, or even add salt to water. Snacks: REI and Amazon both sell omeals ($8) which will cook on the trail just by adding water and are pretty tasty or you can just pack a sandwich, nuts, fruit, or jerky. Poncho/packable rain jacket/water shoes/water tight bag: If you do the mist trail you will get SOAKED. If you don’t have non slip hiking/water shoes, I suggest bringing an extra pair of socks to change into. You can get water shoes made specifically for hiking on Amazon anywhere between $25-$100, depending on the brand. If you get permits for the cables, bring gloves to protect your hands. I got the mad grip brand off Amazon for $10. Layers: It was 50 degrees when we started the hike and 87 degrees during mid day. Fanny pack: easy access to snacks, phone, and camera during the hike so you don’t have to take your backpack off every time.
Apply for permits so you can hike the cables. Anyone can hike the trails, but you must have permits to do the cables. Start hiking no later than 7 am so you do not get stuck hiking out in the dark. Bring a headlamp just in case since you will be hiking downhill. If you think you might get altitude sickness and don’t have medicine, you can take chlorophyll (helps oxygenate blood) right before you start hiking. Do not leave your bag unattended as the squirrels will try to steal/unzip them to take your food. If you choose to do both the mist trail and John Muir trail, do the mist trail going up since the rocks are wet and slippery, and Muir trail down.