Hi Erin -
Yes, the 7-Day LinkPass for Boston's subway (locally, we call it "the T") offers great value because it lets you ride the T as often as you want during the 7-day validity period.
Alternately, you can get single-trip CharlieTickets, the other option that makes sense for visitors.
But keep in mind, the 7-Day LinkPass saves you money if you make as few as 8 one-way trips in seven days.
Although stored-value plastic CharlieCards offer about a 20% discount per ride compared with the paper CharlieTickets, that adds up to only 1 or more trips. For most visitors to Boston who plan to ride the subway several times a day, the 7-Day Link Pass is the most economical choice.
LinkPasses are limited to use by just one person. However, kids 11 and under ride free (up to two children per adult), so depending on the ages of your other family members, you may need fewer cards than you might expect.
The T passes give you a lot of flexibility in your itinerary. Let's say that you're staying in a Back Bay hotel near Copley Square and are planning a day of sightseeing that includes walking along the downtown section of the Freedom Trail in the morning, having lunch at one of the Back Bay restaurants along Newbury Street, heading over to Fenway Park for a behind-the-scenes tour of the famous ballpark in the afternoon, and then going to the Theatre District to have dinner and catch a performance of Blue Man Group in the evening before returning to your Back Bay hotel. You can hop on the subway and easily travel between each of these points - but that's 5 trips right there, in just one day.
You can find out more about the T as well as current prices for the LinkPass here.
Another popular option for getting around while sightseeing in Boston are the hop-on hop-off trolleys. They are LOTS of fun to ride, and kids love them - but most important, they take you around to see all of the city's top attractions. You can get on and off anytime you want to do some exploration on foot or stop for lunch.
A trolley-cruise combo is also available, and worth considering. The cruise is relaxing and fun, plus the captain points out top attractions from the water, giving you a unique view that you don't get on land.
A final sightseeing option to consider if you want to get around the city in a different way is a guided bike tour of Boston. The tours are designed for bike riders of all abilities, and they take you to see interesting attractions with stops along the way if you want to take photos.
Have fun in Boston!