Terran's Ponderous Campaign
Riverhills is based on the town and surroundings that three of the four original players grew up in, while the fourth player was as least familiar with the area. This was done largely for fun, but for two other, related reasons as well.
First, it was felt that being familiar with the actual region and area would naturally aid playing characters from the fictionalized version. We’d already know where the hills are, where the river is in relation to, say, Goldhill Vineyards.
Then, related to that was; at the time, all the players, including the DM were brand-new to the game, a familiar surrounding would immediately pull us into the game. It’s a LOT easier to get into the “rhythm” of the game if you can think “There’s something sinister going on in the marsh, and MOM lives really close to it…” Rather than fumbling through the system (learning by doing.) while simultaneously trying to keep track of an imaginary town and plot, we could rely on a nearly instinctive understanding of the setting, freeing “more” of our imagination to remember how the game works. Also in an “emergency” the DM could fall back on describing contemporary/real landmarks to orient the players very quickly.
Naturally, as we gained practical playing experience, and the further we traveled from Riverhills, the game-world bore less and less relation to the real one.