I vaguely remember a short story (I don't think it was book-length) about some people who lived in an off-planet base, possibly on Titan, and a popular past-time for the major characters was a complex, competitive game that simulated economies, war, resource allocation, etc -- a lot like the modern-day Civilization games.
I want to say it was Poul Anderson, Frederik Pohl or one of the other more off-the-wall authors, and it seems like it was from the 60s / 70s timeframe.
As suggested by user 888379 in comments (and half-confirmed by the OP), this is likely to be Samuel R. Delaney's novel Triton (1976), about 375 pages long.
The story takes place on a base on Triton, a moon of Neptune, not Saturn:
The sensory shield (he looked up:--Big as the city) swirled pink, orange, gold. Cut round, as if by a giant cookie-cutter, a preposterously turquoise Neptune was rising.
The game is called "vlet," a hypercomplex strategy and tactical "board game" with animated and computerized elements. Excerpts about it from its first appearance (note that items in curly braces are my edits):
Lawrence opened out the meter-wide case...
He gazed over the board: within the teak rim, in three dimensions, the landscape spread, mountains to the left, ocean to the right. The jungle between was cut here by a narrow, double-rutted road, there by a mazy river. A tongue of desert wound from behind the steeper crags, alongside the ragged quarry. Drifting in from the border, small waves inched the glassy sea till, near shore, they broke, foaming. Along the beach, wrinkling spume slid up and out, up and out... The river's silver, leaving the mountains, poured over a little waterfall, bright as falling mica. A darker green blush crossed the jungle: a micro-breeze, disturbing the tops of micro-trees...
Lawrence assembled the astral cube: the six-by-six plastic squares, stacked on brass stilts, made a three dimensional, transparent playing space to the right of the main board, on which all demonic, mythical, magical, and astral battles were enacted...
Bron looked around the side of the vlet case, pulled out the long, narrow drawer. He picked up the tooled leather dice-cup: the five dice clicked hollowly. Thrown, three would be black with white pips, one transparent with diamond pips, and the fifth, not cubic, but scarlet and dodecahedral, had seven faces blank (Usually benign in play, occasionally they could prove, if you threw one at the wrong time, disastrous); the others showed thirteen alien constellations, picked out in black and gold.
Bron set the cup down and fingered up the thick pack {of cards}. He unwrapped the blue silk cloth from around it. Along the napkin's edge, gold threads embroidered: {complex equation not transcribed} --the rather difficult modules by which the even more difficult scoring system (Lawrence had not taught him that yet; he knew only that {theta} was a measurement of strategic angles of attack [over different sorts of terrain N, M, and A] and that small ones netted more points than large ones) proceeded. As he pulled back the blue corner, two cards slid to the table. He picked them up--the Wizard of Rocks and the Child Empress--and squared them with the deck...
Lawrence opened the drawer on the other side of the case and tooke out a handful of the small, mirrored and transparent screen (some etched with the same alien constellations, some with different), set them upright beside the board, then reached back in for the playing pieces: carved foot soldiers, mounted men, model army-encampments; and, from this same drawer, two miniature cities, with their tiny streets, squares, and markets: one of these he put in its place in the mountains, the second he set by the shore...
Bron took the piece, looked around at the other side of the case, and began to pick the scarlet pieces from their green velvet drawer. He stopped with the piece called the Beast between his thumb and forefinger, regarded it: the miniature, hulking figure, with its metal claws and plastic eyes, was not particularly dumb: during certain gambits, the speaker grill beside the dice-cup drawer would yield up the creature's roar, as well as the terrified shouts of its attackers.
There are several scenes depicting the game being played throughout the novel. I can dig up some of those passages, if additional confirmation is needed.
I haven't read it in a long time, but based on your suggested authors, could it be Anderson's "The Saturn Game"? Although ISTR it was more like D&D than Civilization in that story.
Hmm, a long shot but is it maybe "The Player of Games" by Ian M. Banks (1988)? While it doesn't happen on Titan, the main character (a skilful player of board games) participates in tournament of a very complicated strategic game:
Although the actual rules are not given in the book, the game is primarily tactical and played on three-dimensional boards of various shapes and sizes. Typically the boards are large enough for players to walk around inside them to move or interact with their pieces. The number of players differs from game to game and also influences the tactics, as players can choose to cooperate or compete with one another. As well as skill and tactics, random events may influence gameplay (often as card or other games of chance), and sometimes may change the outcome critically.
The game consists of a number of minor games, such as card games and elemental die matching, which allow the players to build up their forces for use on the game's three giant boards (in order: the Board of Origin, the Board of Form, and finally the Board of Becoming) and a number of minor boards.
The game uses a variety of pieces to represent a player's units (military, resource or even philosophical premises). Some of the pieces are genetically engineered constructs, which may change form during the game according to their use and environment.
The tournament is very prestigious and the winner will be proclaimed the new emperor.
Another long shot, but have you considered Philip K. Dick’s The Game Players of Titan? Here’s the Wikipedia link
Breaking the Game from the Worthing Saga by Orson Scott Card matches at least your civilization type game part. It was published in 1979, so the tail end of your time frame. The rich can extend their life span by going into suspended animation, but this means letting someone play their civilization in the interim:
Herman Nuber has just woken up from a state of suspended animation brought on by the fictional drug Somec and is looking forward to returning to his virtual world conquest game. Unfortunately for him his position is being played by someone else and that person doesn't want to sell it for any price. When he discovers how poorly the person is playing he gets desperate and arranged to meet the other player...
PS "pastime" is a contraction of "pass time", as in something people do to pass time, not "past time".
