Random thoughts:
FREEZE DRYING: Lasts the longest. Just be aware it's not "turn on and forget". You have to maintenance the machine too. I know "Harvest Right" freeze dryers you have to change the oil in the vacuum pump EVERY TIME you use it. Obviously, the machines are expensive...but also, if you invest in one of these, you can make alot of money selling freeze dried food. Especially rewarding to me would be to sell my own produce this way. Easy money maker, just get your "Cottage Food" license, or similar in your state, follow the rules, and you will always have plenty of food on hand that will literally last at least 20 years. I put dried items in mason jars with lids, bands, and a strip of masking tape on the outside for my label.
SOLAR DRYING: The cheapest. An all metal shed from lowes 250.00 8x10. Put it together tight, use fine steel wool on ANY gap that would allow bugs in (is heatproof of course). Put lots of vents with fine screen/steel wool at the bottom and top for airflow. Add heatproof drying racks (steel ones also at Lowes would work great). Hooks for larger items if needed.
SOLAR CANNING: I don't know if this is an original idea, probably not, but I like to solar can things from time to time. I have an "S.O.S." solar cooker, and I put all kinds of things in mason jars, with the lids and bands. Cook the food in the jar, once it cools it seals itself and you're good to go! Just be careful with things that expand, like rice and such...you can do it just make sure to read how much cooked product it produces
Just things I do...
~Patrick