1:03 p.m. on January 5, 2014 (EST)
I would say the following skills you need to get down pat before any lengthy trip. Overnighters close to a bailout option etc are fine in the interim.
These are listed in no particular order, just the order they came to me. But all are equally important in one way or another.
1) Map and compass skills-be able to locate yourself on a topo map WITHOUT a GPS, and navigate to a specific point by walking a compass bearing. This is best practiced in an relatively small area to start such as an area locked in by roads or rivers or some defineable definitive boundary. This skill set would include things like navigation, route finding, land mark identification, water source identification etc.
2) Setup and break down of your shelter system. Practice setting up and tearing down your shelter multiple times so you can do it without having to consult the directions etc. Practice in the rain, in the dark, in the dark with rain, and in other adverse conditions in your backyard etc. The idea here is that you will be confident and comfortable setting up your shelter on the trail if its getting dark, already dark, and pouring down rain on you. And do so without getting all of your gear soaked in the process.
3) Setup, maintenance, and use of your chosen stove/ camp kitchen. Know how to use your stove, know how to take apart and maintain your stove, know how much fuel you need on a trip etc. This includes how to cook your food, learn what you need to do for a chosen meal so that you arnt caught by surprise in the field that you have to do something special or need way more fuel than you were planning on etc.
4) Developing a trip plan, and leaving it with someone before you leave for your trip. Identifying where you will park your vehicle, where you will start hiking, where you will end, if you can where you will camp each day, potential water sources, etc and emergency contact #s for the person to use to contact Rangers etc. For the trip plan that i will leave with someone i like using the Columbia Take Ten App for iphone. Its easy to do, it saves information you put in and it will email or text it to whoever you want it to go to, including a map with pins showing your start and end points and planned route.
5)Your layering system and how to keep things dry, you need to know what layers work for you to keep you warm and comfortable down to a certain temperature. Always plan for temps 15-20f lower than the weather forecast and you should be well covered in the event of changing weather. You also need to know what rain gear works for you, as well as how to layer protection for your pack to keep items dry, whether this be a pack liner, dry bags, garbage bags, pack cover etc or a combination of them.
6) Organization and your pack. Find a way to pack your gear inside your pack that makes it comfortable to carry, how to adjust your pack for proper fit, and i strongly recommend to always pack your pack as close to the same way as possible. This helps in preventing you from leaving items behind, because if you always put something in a specific place you will be able to readily identify if something is missing. Also learn to pack things that are important in easy to access places and in a way that works best for you. For example I keep my water filter in a outside pocket for quick access, and I also keep my tarp and tarp suspension stuff, and rain gear on the outside of my pack so that if I have to setup in the rain I dont have to expose the contents of my pack to the weather.
7) Water sources and water treatment and storage. Learn how to locate potential water sources on a map, how to locate them in the field, how to figure out your best chance of finding water if you get to a place and the source is dry. How to filter water or treat it with your chosen system, and also how to maintain/troubleshoot and clean your chosen system.
I am sure I left out some things, but those are the major highlights. If you have those things down then you are well suited to go it alone.