1 : of or relating to another country : foreign
2 : a : strikingly out of the ordinary : bizarre
b : exceeding proper or reasonable limits or standards
3 : remote from civilization
In the most literal sense, OUTLANDISH refers to someone or something derivative of the outland, or a designated foreign place. Given the more modern definition (the bizarre), I would say the outland refers to that town or neighborhood that itself can be described as "exceeding proper or reasonable limits or standards." Every town has such an "other." Where I grew up it was "the valley" (comprised of the factory towns in the Housatonic River Valley—Derby, Ansonia, Seymour, Shelton, Oxford, maybe a little Beacon Falls), in Providence it was Central Falls, Rhode Island (visitors are greeted by a sign that reads, "Welcome to Central Falls: The Whole World in One Square Mile"*), in Portland it's Gresham. These locations are deferred to when discussing anything/anyone of lower class/style/morality/intelligence.
That said, I wouldn't necessarily describe any of the above inhabitants as OUTLANDISH. In my mind, OUTLANDISH designates some action that is almost aggressively unacceptable. One night, shortly after moving to Portland, on my way from work to the bus stop I walked by a man sitting cross-legged in the middle of the sidewalk cooking meth. This I might consider OUTLANDISH, and he was most certainly inlandish—right in the middle of the sidewalk, in the middle of Chinatown.
Oh, the contradictions of language.
*That is, if my memory serves well, which it often does not. I consulted Josh, a former inhabitant of the CF, who also could not remember accurately. Many online sources list the town's size as 1.29 square miles, although for the sake of diction I'm sure they evened this size to a whole number. Whether that number was one or two escapes me. I guessed one because it's more absurd.