Best things to do in Boston, including free and rainy-day options

Boston rewards walking. The Freedom Trail strings the colonial sights together in one 4 km line from Boston Common to Charlestown, and you can follow it without a guide or a ticket. Give it a half day, then add one museum and one neighbourhood per remaining day.

If you have two days: Freedom Trail and the waterfront on day one, Museum of Fine Arts or Isabella Stewart Gardner plus Beacon Hill and the North End on day two. If you have four days, add Cambridge, a harbour ferry and a day trip.

The Freedom Trail is the single most efficient thing to do here: 16 sites, red brick or painted line underfoot, no booking needed. Start at Boston Common, pass the Massachusetts State House, Granary Burying Ground, King's Chapel and Faneuil Hall, cross into the North End for Old North Church and Paul Revere's house, then over to Charlestown for the USS Constitution. Some individual sites charge a small entry fee; the walk itself is free.

The Museum of Fine Arts is the big encyclopedic collection, strong on American art and Asian galleries. The Isabella Stewart Gardner Museum is smaller, stranger and built around a plant-filled courtyard; it needs a timed ticket and is worth booking ahead. Both sit on the same stretch of Huntington Avenue, so pick one per visit rather than both.

Beacon Hill and the North End are the two neighbourhoods to walk slowly. Beacon Hill is brick sidewalks and gas lamps around Louisburg Square; the North End is narrow streets, old churches and Italian-American food. The waterfront and the Rose Kennedy Greenway connect them and are free to wander.

A large share of the best of Boston costs nothing. Boston Common and the adjoining Public Garden are the start and end of most walks; the swan boats in the Public Garden charge a small fare in season.

The Freedom Trail, the waterfront, the Greenway, the harbourwalk and the view from the Charlestown waterfront are all free. Harvard Yard in Cambridge is open to walk through, and the Harvard Art Museums are free at certain times. The Boston Public Library's McKim Building, with its courtyard and reading room, is free and one of the best indoor stops in the city.

Boston's weather turns quickly, so keep one indoor option ready. The Museum of Fine Arts and the Isabella Stewart Gardner Museum are the two obvious full-afternoon answers; the Gardner is smaller and often sells out, so book a slot.

The Boston Public Library and the nearby Trinity Church are a compact indoor pair in Back Bay, with shopping and food under cover at Copley Place and the Prudential Center. The New England Aquarium and the Museum of Science are the family picks, both with timed entry.

If you only have an hour, the Quincy Market and Faneuil Hall halls are covered, and the subway itself will get you between neighbourhoods without getting wet.

Boston is an expensive US city for lodging and food, but the sightseeing itself can be cheap. Budget for one or two paid museums and keep the rest to walking, parks and neighbourhoods.

The MBTA subway and buses are the cheapest way to move; a reloadable CharlieCard or contactless tap is the normal method. A harbour ferry to Charlestown or the Navy Yard is a cheap boat ride rather than a tour.

Walk the Freedom Trail early. By mid-morning in summer the North End and Faneuil Hall are crowded, and the Charlestown section is a long, exposed walk in the afternoon heat.

Stay in the core or along the subway if you want to avoid a car. Boston's centre is compact and the MBTA covers the sights, Cambridge and Somerville; driving and parking are the main costs to avoid.

Book the Gardner Museum and any aquarium or science museum slot in advance, especially at weekends and school holidays. Check opening days: some museums close one weekday.

Layer for wind off the harbour and carry a compact rain jacket rather than an umbrella in exposed spots. In winter, ice on brick sidewalks is a real hazard.