The boondocks are a place a long way from the nearest town: few shops, few buses, far from city lights. English almost always says “the boondocks,” not “a boondock,” and people often say “out in the boondocks.” It is informal American English, a bit jokey. Though actually it can sound as if the speaker looks down on the place — not only “far,” but “in the middle of nowhere,” a little unsophisticated. It is not a kind word you would put on a town sign. It has nothing to do with boon (“a help”), even though the start looks the same.