Travel plans for holiday in USA?

Im traveling to the USA from New Zealand on March 6th and will be in the USA for about a month. Can you let me know what you think of the travel itinerary?

Arrive New York March 6th
Savannah (or perhaps Rhode Island or Maine) - 4 Days
New York - 9 Days
Boston - 3 Days
Chicago - 5 Days
Washington - 5 Days
And then another 5 days with family in Boston

I would really like to spend the first few days doing something outside as Ill be jetlagged. Im meeting friends in NY and going with them to boston and then about a week later I have to go see family in Washington. For the first few days could you recommended anywhere nice outside? I thought Savannah but also have family in Hartford who I could stay with (or I thought Maine may be nice). Im mainly planning to travel by train but am happy to fly.

I am assuming you mean DC and not the state of Washington. That seems to be a well thought out iteniary in my view. Not sure about the part where you say Savannah or Rhode Island or Maine but you seem to be centering the majority of your vacation in the New England states which is pretty wise in my view. If the Savannah you are referring to in Georgia then go ahead if you want but if you want to reduce travel time then go to Rhode Island or Maine.

Just want to let you know that the weather in March is still cold.
I would like to go to South more.
Other than Savannah, maybe you can go to other south cities like Orlando (FL) and Myrtle Beach (South Carolina) but you will need more than 4 days
NY -9 days will be good if you like city live
Boston and Chicago , personally I wont need that long to see that 2 cities. (Why not going to Niagara falls instead?)

Wash DC 5days is great, because they have a lot of museums (Smithsonian) and monumen that you can visit, and they are free (I think DC is the only city that let you visit lots of places for free)
Why dont you go to west coast? (Calif)

Rather ambituous. To Savannah or Chicago from New York is quite far. Washington to Maine is easily done by train. Hartford is a good midpoint between New York and Boston, and it has a big art museum and Mark Twain's house. Maine is gorgeous and Rhode Island is pretty too but its not beach weather in March. You can ski in big mountains in Maine, New Hampshire, and Vermont if you like that.