once again too many replys to wade thru but heres my take.
sourdough--Google that and you will find places that give away old--read 1800's--starters..if it is survival and just not homesteading you will run out of yeast before long..
Bannock--making bread takes up a lot of time,energy and fuel in a survival situation. bannock may not meet your need for slice of toast and jam but it will fill you up.
i make bread in a machine mostly in the winter when a hot slab of bread and butter is almost survival food.