The main problem with a vegetarian diet is that you have to plan for COMPLETE protein, which is protein that contains all nine essential amino acids. There aren't an awful lot of plants that contain it, but you can make up the complete total by eating certain plant foods at the same meal (or within a few hours of each other) that DO make up a complete protein.

Eating a combination of legumes + seeds, or legumes + grains, or legumes + nuts will provide complete protein. Remember all those Mexican meals that always had beans and rice? That was legume + grain, a complete protein.

Plants that contain complete proteins in themselves are soybeans (and soy products), amaranth and quinoa (South American grains), hemp, spirulina. At this very moment in time, I am sprouting three kinds of quinoa that I found in a new health food co-op, red, white, and black. All three kinds have sprouted. It probably won't grow everywhere, but I am hoping to sow three small plots of them, both for a seed source and as chicken feed. In fact, every kind of seed that I have bought in a store that has bulk-foods has sprouted, with the exception of the milled millet, and the milling is probably the reason. (Be sure never to eat seeds or sprouted seeds that appear dyed, as some seeds have been treated with the pink fingicide Thiram or other chemicals.)

It may be easier to plan for animal protein if you get away from the large-animal idea, and think about small-animal complete protein sources like eggs, goat milk (and cheese and yogurt), rabbit and fish.

If you feel you don't have the knowledge/interest/situation for animals like these, you might have neighbors that do. It's really hard for a family to grow everything that you would want to eat, esp when food production is new to you (there is a learning curve). Working out a neighborhood food barter system could be ideal, and you might have people you could depend upon in a sticky situation.

Sue