Boston or DC for five yo boy and Single Mom
 

tia

I vote for D.C. The Smithsonian museums are free. Best for kids: Air and Space, Natural History (Imax theater), American History (currently closed), African and Asian art. If your son (or you) gets bored, leave and go to a different one without feeling guilty or going broke. There's a carousel on the mall right outside the museums. In winter, there's ice skating on the mall. National Zoo is good, but not free. My son, when he was young, loved the National Geographic museum, but it's not part of the Smithsonian and there is an admission charge. Union Station is fun to explore, too. Shops, restaurants, train-watching.

With a 5 year old, just drive past the historic monuments, the white house, and government buildings and look from the outside. He'll be too young to understand much of the significance.

You can get a reasonably-priced hotel with an indoor pool outside the city, (Bethesda, Silver Spring, Arlington) that includes free or inexpensive parking, then walk to the Metro and ride into the city. The suburban hotels often have restaurants nearby. D.C. doesn't have much going on at night for kids.

Boston is much more expensive than D.C., though it does have a fabulous children's museum. Museums in Boston are definitely NOT free. Fanueil Hall market area has lots of interesting outdoor street performers that your son may enjoy. I was a single mom of 2 on a tight budget, which is why I mention the costs of museums, but if that is not an issue for you, please ignore.

D.C. would be my choice. The National Zoo is a good choice and is part of the Smithsonian with free admission. Go to the panda exhibit; better than the one in San Diego in my opinion and without the long wait/lines. Ride the subway, your son will enjoy that. Take a drive out to the Steven F. Udvar-Hazy Center (part of the Air and Space Museum) near Dulles airport, a large hanger with many planes including a Concorde and space shuttle. I thought this was more interesting than the Air and Space museum on the mall. Also visit the National Botanical Garden near the Capitol building and the Museum of the American Indian just down the street. Take a "Duck tour" of D.C.; I think your five year old would really enjoy this.

Although I live in Boston, I must concur with the recommendation of DC. Plenty of things to interest a younger kid, and no guilt about making reasonably short visits.

I'd add the observation tower at the old Post office Building, which as an OK food court, too.

Does he have special interests? Planes, trains, automobiles? Dinosaurs, insects, dogs? Ice cream, pizza, sushi? Impressionist art?

DC

I have to agree with Washington DC.As a 70 year old grandpa I would prefer taking my 5 year old granddaughter to Washington.There are more green spaces making it much more safer .Between the Capitol and the Lincoln memorial there's such a vast space with grass ,benches...I would take the Old Town trolley the first day.You can get off/on all day and the driver is a great guide.A trip by boat to Mount Vernon would be enjoyable for kids and adults alike.Paul

Actually, there is NO admission charge to the National Geographic Society museum. They often have many exhibits which are of special interest to children.
Also, you should know that while there is not an admission charge to the Udvar-Hazy Air and Space Museum, there is a $12 parking fee.

Having been to both, I would say DC.

A lot more options for sightseeing and the transit system is easy to handle to get around.