Great sources all.
In addition to the Foxfire books, learn to identify the plants of an area. Start with some colored pencils and index cards (or "Cambridge notes"), though a weatherproof mini-plant guide of a thousand pages or so is also recommended*.. Basically specialize in a certain area (say the southern Appalachians), get a plant guide, and see if you can id the species in the spring and summer. Having been on a few federal environmental contracts out west, we spent months studying and then quizzing each other on dried specimens. Technically, most "keys" identify primarily by flower but in reality, you can't wait until a plant flowers. Being able to identify a plant in various stages of wilt without a flower is a definite plus (leaf shape, sometimes the stem).
Is the fruit edible? Is the fruit only edible at certain stages but contains tannins at other stages? What did the natives use the plants for historically? Are there any other uses for the plant (fiber, medicinal, etc..)? Is it or any portion of it, toxic or could give an allergic reaction? Any funny history associated with it? Once you say you are a nature lover, expect quizzing (goes with the territory and can minimize potential poisonings).
I say the South since there's more biodiversity starting midway through Texas (the Edwards Plateau) and going east. The more southern states have less cold days, so there will be more plants to start identifying, cooking, etc.. (I made the mistake of going west for a college plant identification class, and ended up hauling azz east to grab some specimens before the first freeze … ended up choosing the mountains and deserts of the west over the rich biodiversity of the east, so haven't regretted pursuing that dream).
*ed:add that's Petersen's Guides
