Harvard is in Cambridge, not Boston, but try convincing Grandpa Bob back in Fancy Gap, Virginia of that.

You can't. Never mind the fact that Cambridge is equipped with its own historical landmarks, theaters and neighborhoods. An anthology of tales about 8-hour organic chemistry labs, lunches in the Pit with preteen skinheads and idle afternoons lingering over coffee and croissants at Au Bon Pain, do not complete Harvard Summer School Experience make.

There's no excuse for leaving Harvard without ever setting foot in one of the oldest and most fascinating metropolises in America. Fleeting images of skyscrapers, the townhouses in Back Bay and the Boston side of the Charles River on you cab ride from Logan Airport simply won't do.

On you first trip into Boston, don't be afraid to play tourist. The first thing tourists hit-especially those who are also history buffs-is the Freedom Trail.

The trail, a red line painted on sidewalks or lain in brick throughout the city, will lead you on a three- to four-hour tour to the city's most prominent historic landmarks as well as to Boston's traditionally Italian neighborhood, the North End.

You can reach the trail by rail. The Boston subway system, part of the Massachusetts Bay Transit Authority (MBTA) and called the T, is the oldest in the nation. And its four lines (red, green, blue and orange) will take you everywhere you need to go for just 85 cents a ride.

From Harvard Square, take the Red line inbound and get off at Park Street. There, you will find Boston Common, a 48-acre green oasis of fountains, monuments and relaxed Bostonians. And other tourists. Bought by the city in 1634 as pasture land for cows, goats and sheep-and later used as a military training ground-the Common is the oldest public park in the nation.

At the Boston Common Visitor Kiosk ask for a guide to the Freedom Trail and let the red line take care of the rest. Along the trail, must-sees for history buffs include: the State House; the Granary Burying Ground, final resting place of not only Samuel Adams and John Hancock but also of your childhood friend, Mother Goose; Old South Meeting House, where the idea for the Boston Tea Party was first conceived; Paul Revere's House; and the Old North Church, of Longfellow fame.

Perhaps the most lively and frequently-visited spot along the trail and in all of Boston is Faneuil Hall Marketplace, where you'll find jugglers, magicians and street musicians entertaining crowds in front of a variety of restaurants and shops.

Enter the pillared Quincy Market building and your nose will be assaulted by a million appetizing odors--fresh lobster, pot pies, egg rolls, empanadas, pizza, fudge brownies and more. This food court houses more than 20 stalls from which even the most finicky tourist can choose a tasty meal.

In the mood for a little shopping? Flanking Quincy Market are pricey gift and craft shops as well as such traditional mall favorites as Victoria's Secret, The Sharper Image, Banana Republic and The Gap. Don't forget to visit the seven-story Limited.

If you're a theater fan on a tight budget, stop by the Bostix kiosk, where you can get half-price tickets to many plays at Boston area theatres on the day of the performance.

Faneuil Hall Marketplace is easily accessi- ble by T as well. Take the T to GovernmentCenter and walk past one of the few architecturalmonstrosities in Boston--the anti-or-ganicupside-down concrete City Hall-to this festiveshopping and eating complex.

Back on the Freedom trail, you'll move on toHaymarket, Boston's open-air produce and fishmarket. There vendors sell their in-season fruitsand vegetables at wonderfully low prices.

The trail will then lead you to the North End,Boston's version of Little Italy, home of bakeriesand Italian Restaurants of varying quality andauthenticity. Several yuppie-chic restaurants haveopened to cater to the new residents who havemoved into the some the of the neighborhood'srecently gentrified buildings.

Look for the tell-tale signs ofgentrification--the too-freshly painted fireescapes and Volvos parked along the street as youleave the North End. Then cross the Charles Riverto the predominantly Irish Charlestown and theBunker Hill Monument, a 220-foot obelisk thatcommemorates one of the first battles of theRevolutionary War.