I wouldn't put it in space, either. Canonically, the setting already has Isolate communities on Earth, and that seems a solid projection of current trends.
According to this story, which provides some good evidence, within the next generation or two, North America will have huge expanses of territory that are even less populated than they are, now.
http://www.pewsocialtrends.org/2018/...l-communities/ .
So, figure that by 2100, some ratio higher than 90 percent of the U.S.population lives in urban centers or (most likely) suburban communities, with most of the rest in rural counties immediately adjacent.
That means large urban/suburban areas, surrounded by a narrow band of agricultural or resource extraction communities, with vast areas of miles and miles of nothing but miles and miles, between them.
Call it an East Coast megalopolis with support communities that may go as far as the foothills of the Appalachians;and a West Coast megalopolis with farmlands west of the Sierra/Cascade ranges.
I think there could also be a Gulf Coast urban corridor with hinterlands that reach inwards no more than about 100 miles (further along the rivers, not so much in the forests and bayous) from wherever the coast winds up after the oceans rise; and a Front Range Urban Corridor that stretches from Cheyenne Wyoming to Pueblo, Colorado. I'd also see a big blob at Dallas-Fort Worth, too.
Add in a number of blobs in the upper Midwest -- Minneapolis-Saint Paul, Milwaukee to Chicago, a renovated and smaller Detroit, and Cleveland to Pittsburgh (not sure about that one...) -- plus some splotches around other large cities in the Mississippi basin and the Ohio River valley.
Still, that leaves huge expanses of land largely empty of people and returning to wilderness. Find a spot in a holler in Appalachia, or a forest in Michigan's Upper Peninsula, or a marsh inland of the rising waters of the Gulf, or anywhere in the Snake River valley.
Heck, just squat in a decently-preserved ghost town just about anywhere; there's lots.
Stay away from the rural areas that still have populations (resort areas, retiree centers, or places with uniquely valuable resources), and most people would have no reason to even come looking.