***Boston for a day? our faves are Museum of science with kids,then head over to Quincy market waterfront area, tourist shopping+ historical buildings,you can arrange a tour if you like,or just wander the area with a map,the big building right there is great inside(can't remember the name,maybe a capitol building from Revolutionary war?)
Right there near the water by Quincy market is a place where you can pay to take a water tour of harbor, -OR- you can do what we do which is walk PAST that tourist boat and buy a ticket for the city water taxi service,which takes you across the harbor to the USS constitution (free awesome tour) and back again...and it costs around 1.00 per person to take this water taxi.



Either or both of these things would easily fill one day. If you did both,it would be museum in a.m. at opening,leave by noon or so and head over to waterfront.(we've walked that distance,or taken the subway)
***NYC? one day? hmmm,I'd head straight down to battery park via subway,(as early in the a.m. as possible) get off and head over to the staten island ferry terminal, get on the 1st avaialble ride across the harbor,and get a GREAT ride by view of the Statue of Liberty for FREE.

As soon as you get to Staten Island, head right back to the entrance for the ferry on that side,and ride back to Battery park/manhatten.
Then take subway back up to Central Park area, wander over to the Natural History museum,pay (suggested donation/whatever you feel like paying to get in) check it out for a while, head out to the park and grab snacks from a street vendor and just wander around, I love the ponds,and the statues.
Hit Times Square later as it gets darker,for the lights- it's cool.
You need to google and get some good walking maps of the cities to do this, but it's cheap and fairly easy.
