New Hampshire and Boston

[Mightactuallygoonholiday]

Anyone know these areas at all and can advise about a possible holiday in May next year?

It would be me and my 4yo, visiting friends in Littleton NH and also staying a few days in Boston on the way back.

A few questions:
What is there to see/do for young children in Boston?
Any tips for seeing Boston on the cheap? Are there family friendly (safe!) hostels etc? Any recommendations?
What's the weather usually like in May?
Also, just how expensive is food/petrol in the US? My friend has kindly volunteered her husband to collect us from Boston but we'll obviously have to pay them for petrol and pay half for groceries while we're there - is it going to bankrupt us??

Any other thoughts would be appreciated!

Thanks!

Bumping...

Asked my cousin who recently went to Boston with her 4 year old.

They recommend:

Boston Children’s Museum
New England Aquarium
Boston Science Museum
Boston Common park

They stayed in an AirBnB in The Waterfront in the north end, which apparently worked well as hotels were pricey.

Thank you so much @cherryassam that's really helpful!

Boston is lovely, loads to do

I have family near Littleton.
Catch the coach from Boston (either the airport or South Station which is downtown Boston) to Littleton. It's a daily service, or if your friends/family are feeling generous they can pick you up at Concord which is served five times a day ish. The company is Concord Coachlines. You can book online. Brilliant service, always incredibly on time and we go in proper snow season so can vouch for it, looks on board and WiFi, it's a lovely journey.

Petrol(gas is about $4 a gallon, which means it's still much cheaper than in the uk.

Boston is great but so are the White Mountains (Littleton is within them, with many beautiful towns nearby, eg Woodstock, Lincoln and Plymouth)

May can be wet/hot/humid and completely unpredictable but unlikely to be less than mid 20s. Weather is a bit weird up there.
It's a lovely part of the world and we love it. No sales taxes on goods there (unlike Boston which is in Massachusetts so different sales tax).

Thank you that is really helpful!