THE SWEET, rich scent of chocolate assails your nostrils when you cross the city limits of Hershey, Pa. Chocolate is Hershey's raison d'etre, and you're not likely to forget it as long as you're there.

The streetlights look like chocolate kisses, the main street is called Chocolate Avenue, and a handful of Hershey kisses automatically comes with your change at the Hershey Motor Lodge -- even if you ordered the low-cal special. Since 1973 somewhere around 10 million tourists have come here to ride the automated track through a simulated cacao bean plantation and chocolate factory called Chocolate World, just one of a number of attractions. This is a unique spot within shooting distance of New York, Philadelphia, Baltimore and Washington.

But the cars aren't finding their way up Route 322 the way they did last year.Official figures show only a 12-percent drop, but many of the license plates in the parking lots are Pennsylvanian and their owners may go back home after a day's fun. If Herco, the corporation that handles the tourist end of Hershey, hadn't been pushing its attractions aggressively in newspapers of neighboring towns, the fall-off might be more severe.

In the Hotel Hershey, my waitress worries.

"We're in triple jeopardy," she says. "Gas, polio and Three Mile Island." If true, then Hershey is being treated unfairly.

The polio cases occurred in Lancaster, 28 miles away, in April and May, but tourists are still phoning in nervously to inquire about the outbreak. The Center for Disease Control in Atlanta says it has "always felt that the risk was low" in the Amish areas of Pennsylvania, but that the risk "is even lower now" since there has been no new case of polio reported in more than a month and "there is even less opportunity for the virus to spread" since more Amish have been immunized recently. The CDC says it has always believed that parents taking children on trips to any part of the country should make sure their immunizations are up to date.

The fear of Three Mile Island has waned, though the NRC announced in mid-July that monitoring devices showed increased radioactivity in the air at two of the buildings on several days in late June and early July.

"Three Mile is 12 miles away as the crow flies -- 18 by road," says Skip Becker, public relations manager for Hershey, "and the prevailing winds are not in this direction." He has reports from a corporate-commissioned study showing that "a statistically insignificant" number of people have changed their travel plans -- or will -- because of it. The man behind the desk at my motel in town said he thought Three Mile has passed from a tourist worry to a curiosity in front of which people are posing for snapshots. (Townspeople, who are subject to cumulative risk and who lived through the crisis, feel differently, however.)

So why aren't the rooms in Hershey in more demand? Other seasons, if you hadn't booked by noon, you were in trouble. This year you can write your own ticket, take your pick.

The major cause is the uncertainty of gasoline, with a pinch of health worry thrown in. In reality, it is easier to get gas in Hershey than it has been in Washington. Everything is being done to smooth the tourists' way.

The Hershey Gas Line -- 717-534-3005 -- provides information for travelers from Connecticut, Maryland, New Jersey, New York and Pennsylvania on what stations are open. At Hershey Information Center, a smiling young girl will hand you a map when you arrive that pinpoints the nearest open station. Only three cars waited in front of me, in spite of the fact that I hit the opening day of the Pennsylvania-wide strike of independent dealers. The gas is there, but the tourists aren't sure it will be.

From Washington, it takes about 12 1/2 gallons round trip, if you don't use your car at all when you get there. Trams and courtesy buses will take you nearly everywhere you want to go, though you will get pretty hot waiting on the torrid parking lot to catch one despite the usually short wait. Even if you couldn't find any gas at all, you could make the trip to Hershey and back with ease.

And Hershey offers some real delights. Seldom has a corporate effort been so beguiling as at Hershey. Milton Hershey, the Derry township boy with a dream who built his chocolate factory here back in 1905, was a philanthropist with taste, and he left some interesting things to his town.

Hersheypark, of course, has been operating since 1907, and was bringing in the crowds as a theme park playground long before Disney. Walking through it today, watching the families pushing the youngest in a stroller and leading balloon-toting children by the hand, or sipping chocolate in one of the little restaurants, you wouldn't believe business is off in Hershey.

But step into the Museum of American Life nearby and you'll have plenty of elbow room. And what a shame -- because this houses a couple of dazzlers nobody should miss. Don't go home without taking a look at the lamp Milton Hershey brought back from the Chicago World's Fair to install in his Hershey home. It's a torchere of cut glass standing some 12 feet high, and when you have seen this you have seen the ultimate lamp.

But the real prize here is the Apostolic Clock, on beyond the Conestoga wagons and the bear traps at the end of the hall. It took a man called John Fiester 11 years to make it back in 1878, and after you watch it put on its performance you'll wonder how he finished it so quickly. Every quarter hour this clock puts on a show not to be believed. Just to give you an idea: at quarter to the hour the entire 12 apostles parade before Christ, who acknowledges each one; the devil peers from two different windows and finally slips down to get a closer look at Judas turning his back on Christ; a cock crows; Justice raises her scales; a music box plays; Death surveys a middle-aged man speculatively and withdraws -- he gets him on the hour -- and that's it for another 14 minutes.

The Hershey Gardens are another sight that gets lost in the enthusiasm for Chocolate World. It does not seem to attract visitors, though there could be no better place to recoup from the crowded, hot attractions below. When Hershey was asked for a $1 million donation to establish a national rosarium near Washington, he retorted he had been thinking of something a bit closer to home. The town of Hershey should be eternally grateful, for these acres of roses overwhelm the eye, spreading beneath the flags of the seven nations working in rose hybridization. They'll be blooming 30,000 strong right up to Sept. 1, and their starring role will be assisted by a chorus of daylilies and chrysanthemums.

Herco, here and elsewhere, is not above making you enter through the gift shop, but this way you do get to see the small cacao plants for sale as souvenirs. Pay your $1.50, then wander down the path but don't miss the Japanese garden, one of six international theme gardens, where you sit by a waterfall and restore your soul. On the way back, look for the fountain of the boy holding a leaking boot, one of the garden's prides.

Herco's showpiece is the Hotel Hershey at the top of the hill, an elegant hostelry of Mediterranean influence set down in the middle of rural Pennsylvania. Milton Hershey brought back a picture postcard of a hotel he had admired on a Mediterranean trip and told his architects to build one like it. Its tiled lobby above the ground floor is cool with fountains, green with palms, and the reflecting pool set in a Grecian walk behind it is home to duck families. Its golf course is renowned and its vistas impressive. Rates are $98 double, full American plan (3 meals).

Families who wish to pay less often stay in the Hershey Motor Lodge, where a double goes for $44- $46 (without meals), though some good motor lodges in the town itself are charging only a bit more than half that. The Motor Lodge is trying to combat gas worries with a courtesy shuttle to the attractions, but there are still empty rooms and the dining room is said to be full of day-trippers.

In mid-July, Hotel Hershey was host to a gathering of classic car enthusiasts who parked their Rolls and ancient Packards on the lower level and gathered on the porches and in the dining room to compare notes. The dining room was not full, but beyond the windows, decorated with famous stained glass pictures of local birds and flowers, lay the carefully manicured flower beds full of Hotel Hershey roses developed to honor the hotel. Early diners, looking like part of a stage set, leaned over the reflecting pool to cast leftover dinner rolls to the ducklings. Inside, as a string orchestra played softly, the waiters ministered to the late diners.

If you want to take in the beautiful Pennsylvania Dutch farm country while you're in the area, drop down to Lancaster county on the way home -- it's very little out of your way -- and visit the home of the Amish. The Plain People have never had to worry about gasoline, since long ago they decided to withdraw from an increasingly mechanized world and go about their business happily in simple horse and buggy.

The Amish do not like to be photographed (some consider snapshots graven images) and are not easy to meet, so the best way to find out how they live might be to visit one of the model farms. A tour through the Amish Village, just north of Strasburg on Route 896, will give you an idea of how these people live and why they have chosen to keep themselves apart from the rest of the world. It was once the home of an Amish family and is operated as a sort of museum home. The accompanying lecture by the guide will be a big help in understanding Amish customs, dress and beliefs.

Pennsylvania Dutch food is one of the indigenous musts of your visit, especially if you are not counting calories. Shoo fly pie and apple pan dowdy, you remember, make the sun come out and your stomach say howdy. You can buy it to take home at the Amish Village country store or eat it for dessert after noodles and sour cream, chicken, ham, cole slaw, apple butter, and more -- much more -- at Miller's Smorgasbord on Route 30 toward Ranks, or at Good 'n' Plenty Restaurant on Route 896 at Smoketown. At the latter, you'll be seated farm-style at a long table and will help pass. If you want to stay overnight there are plenty of motels, or you might want to try Host Farm & Corral, route 30, Lancaster, a luxury hotel where you can pay $120 per couple a night, MAP, weekends.