One Day in Boston Itinerary Help

You're hitting a lot of great spots, especially dinner in the North End.

Just remember, it's cold here. And the sidewalks are sloppy. Stating the obvious but be warm, and good boots will go a long way to enjoying any walk about town. I'd recommend Cambridge - Harvard square has a lot of good food and shops. North end has a lively dinner scene, can't really go wrong with any of the restaurants. I'm a personal fan of the the osso bucco at Mama Maria. Get a canolli and espresso afterward!

I'd also skip Quincy Market, sort of a tourist area and underwhelming.

When you say waterfront I imagine you're referring to the seaport district. This is a more modern and built-up part of town. It's been transformed and marketed heavily - nice but not the old Boston you might be expecting. 30 years ago this part of town was just called Southie where you could buy oysters from the boat. Now it's filled with expensive restaurants and shops like Filson. Gets very busy. Worth going in my opinion but a bit more generic feeling than the north end or Beacon Hill.

This is a LOT in one day tho. Seaport and Harvard are not that close to each other; or, should I say, not quick to get from one to the other unless you're traveling by T (subway).

Final thought. You could always center your day around food, never a bad idea right?

Get ramen for lunch in Harvard Square.

Chowder and a beer downtown, here I recommend union oyster house in Faniuel Hall near the freedom trail. It might be the oldest restaurant in America.

Italian and that canolli in North End for dinner. Get a reservation if you can.

Lived in Boston for 13 years and love the city.
Beacon Hill is charming neighborhood built in the Federalist style (early 1800's). Gas lighting and cobblestone sidewalks and streets. I think it was judged the nicest neighborhood in the US by somebody. Nice meal at 75 Chestnut or 1928 Beacon Hill restaurants.
Next to it is the Public Gardens. It's one my favorite places on earth (and I've travelled quite a bit...)
Next to that is Newbury street. A wonderful shopping street (though nicer stroll in the summer).
Walk inside the old part of the Public Library and stroll around. It's USA's first public library and truly a gem.
All these places are infinitely more interesting than the Quincy Market.