For any overnight hike, here's a quick breakdown of the gear you should pack in your hiking backpack: Tent (or hammock with tarp shelter) Sleeping bag Sleeping pad Backpacking stove Kitchen supplies (i.e. utensils, pot/pan, bowl/mug, etc.) Water filtration system Water bottle(s) Thermos Hiking shoes Small first aid and/or repair kit Meals and snacks (preferably in a bear-resistant canister) Weather-appropriate clothing ToiletriesFor beginners, a 35-50 liter pack is a great place to start. Larger will make life easier when you're still learning how to pack a backpack properly. Plus, it will give you more room if your gear isn't exactly of the ultra-light variety.