ON A CLEAR October afternoon, when the air is cool and a little smoky from burning leaves, when the sun brightens the ivy on Nassau Hall and trees that seem stippled with fire light up wide greens and mown fields, Princeton looks and feels like a dream, a campus that lives up to the imaginings of F. Scott Fitzgerald. If only on that kind of autumn day, Princeton is one side of paradise.

Orange is its color and the tiger its mascot, yet neither the town of Princeton nor the university reflect anything so garish or ferocious. Going there for the first time is a little like reading the New Yorker -- for a moment, or for years at a time, one is transported to a world where the living is lush, cool and moneyed.

When I was an undergraduate, my friends and I would walk down the white line of Nassau Street on Saturday night complaining about the isolation, the shattering quiet.

"Nice town to grow old in," one of us would say.

"No," another would say. "It's a great town to die in."

And then an empty bottle of beer might go crashing against the curb, the only sound in Princeton past midnight.

For a student with trouble on his mind, even a bit of innocent trouble, Princeton is nowhere. People "take luncheon." The streets are "tree-lined." "Old families" live in houses with names.

Of the so-called Big Three -- Harvard, Yale and Princeton -- Princeton is easily the preppiest, the wealthiest, the most pastoral.

Harvard's Cambridge combines a sizable working-class community with a large young gentry population. The streets around Harvard Square, Massachusetts Avenue, Grove Street, Brattle Street, are lined more with bookstores, movie houses and political activists than with birches, elms and oaks. Yale's New Haven is an eastern industrial city featuring fine theater, frequent political activism and the best pizza this side of Naples.

The literal-minded will point out that Princeton consists of more than its university and a wealthy WASP enclave in easy commuting distance of Wall Street and the Main Line. Less than a mile down Witherspoon Street, a walker will discover that many blacks, few of them as prosperous as their fellow Princetonians, live and work in town. Unfortunately, acknowledgement of this part of Princeton is rare. It is not part of the gabled, ivied fantasy.

Still, to come to Princeton on one of those autumn days of fantasy is to suspend judgment and disbelief. I grew up in New Jersey, but not until I visited Princeton in my senior year of high school would I have believed it to be a part of that state ("the state of seige" we used to call it). New Jersey is a litany of hard realities and bad jokes -- from the shining swamps of Secaucus to the noxious emissions of Elizabeth, the "Garden State" is easy material for comics who have never known the pleasures of a place like Princeton.

Especially on football weekends, you may have trouble getting a reservation on short notice at either the Nassau Inn or the Peacock Inn, the two best places in town to stay, but if you can avoid the temptations of the tailgate and wait for the Tigers to travel up to Hanover or Providence for an "away" game, you will find the uncrowded town of college fantasies.

(If, on the other hand, you have visions of drunken bankers dressed in beaver coats and singing "Old Nassau" while executing a school salute that looks more appropriate at a martial rally than at Palmer Stadium, plan in advance -- tickets are not usually a problem, but hotel rooms and restaurant tables are hard to come by, especially when Harvard or Yale is in town.)

Princeton's most illustrious undergraduate, Fitzgerald's Amory Blaine, had a "deep and reverent devotion to the gray walls and Gothic peaks and all they symbolized as warehouses of dead ages."

The best and easiest place to start a walk around the warehouses of the Princeton campus is on Nassau, once part of the Assanpink Trail used by the Lenni Lenape Indians.

In front of you, as you enter the Fitzrandolph Gate, designed in 1905 by Stanford White's architectural firm, is Nassau Hall, now the center of administrative offices for the university. Nassau Hall, the axis of the university after it moved from Newark, was almost called "Belcher Hall," after Jonathan Belcher, the governor of New Jersey who helped bring the "College of New Jersey" to Princeton. Happily, the governor opted for modesty and insisted the building be named for William of Nassau, prince of Orange who was instrumental in eliminating slavery from England. Nearby is Alexander Hall, a concert hall, widely considered the ugliest building on campus.

Princeton has numerous buildings of neo-gothic design -- Holder, Pyne, Blair and Patton among them -- and all are worth a look. Murray-Dodge Hall, located behind the "Greek temples," Whig and Clio Halls, houses Theatre Intime, the launching ground for performers such as Jose Ferrer, Joshua Logan and James Stewart.

Nearby is Firestone Library. A friend of mine used to call it the "rubber room," in memory of the donor's business and in tribute to many nights bouncing off the walls in the stacks.

The University Chapel, a cruciform High Gothic building dubbed "Moby Dick," is beautiful, featuring a Poet's Window which shows the figures of T. S. Eliot, Homer, Dante and Shakespeare ascending a ladder.

Prospect Gardens, with the president's old residence in the middle of it, is a beautiful respite from the academic storms. Squirrels, both black and gray, are plentiful and fat. Many of Prospect's trees are unobtrusively labeled. Very Princeton.

Along with the Garden, the best place to get away (an enclave within an enclave) is the art museum, McCormick Hall, which features a fine Far-Eastern collection, and works by Veronese, Hieronymous Bosch, Alexander Calder, Willem de Kooning and Andrew Wyeth.

If you leave campus, and many Princeton students don't, ask for directions to places such as Albert Einstein's old house on Mercer Street, the Institute for Advanced Study (a nice place for a picnic), the Princeton Battlefield, the Graduate College, Drumthwacket and the Friends Meeting House and Cemetery.

To be honest, Princeton is not a great town for restaurants. So one caveat and three modest recommendations: Skip the overpriced, half-baked Lahiere's, and try dinner at the Greenline, drinks at the Annex and Sunday brunch at the Nassau Inn.

In my senior year at Princeton, a funny old man named Freddie Fox died. He had an office in Nassau Hall where he kept stuffed tigers and class banners, especially from 1939, the year he was graduated. He was the official Keeper of Princetoniana.

Everyone knew Freddie. At opening ceremonies he used to teach incoming freshman the school song. He used to ride a black bicycle around campus wearing a straw boater with a black and orange band and a tiger-stripe sport jacket. He wore tiger-striped ties, Princeton pins and Princeton socks.

Freddie loved that place. Sometimes his love, his outfits, his innocent dedication to an institution so rich and powerful seemed a little queer. Princeton, after all, is an institution imposing enough to negate any devotion so personal as Freddie's. But there it was.

Try it for yourself. Make a trip to Princeton. If you catch it on the right day, with the smell of autumn in the wind and the heft of wisdom in the walls, you might discover a campus worth loving. A fantasy. Freddie Fox's Princeton.