USA east coast (NYC-Boston) with 4 year old

[Antsinmypantsneedtodance]

Anyone with recent experience. Is this idea insane with a near 4 year old?

5 nights NYC - 5 night 4 full days
Drive to Cape Cod -6 nights 5 full days
Drive to Boston- 4 nights 3 full days.

Looking at going early September. Day time flights both ways. Longest flight we've done before is 4.5 hours and that was okay. Lobgest here is 7.5hrs. We've done all the locations before about 8-10 years ago, so happy to miss some of the normal tourist sites and experience some of the more kid friendly places and see places through different eyes.

Costing it up its coming to similar to a european break in a nice hotel half board. Obviously will have food on top. I'm not sure if i'm seeing this idea through rose tinted glasses as it's something i'd enjoy and it would be awful,or if it actually could be fun with a near 4 year old in tow.

Anyone any thoughts?

No recent experience but we did a very similar trip around 10 years ago with a 3 year old. I found people to be incredibly child friendly, it was a great trip. The only thing is that it really was a trip of a lifetime and the 3yr old obviously has no memory of it! But circumstances just meant that was when we got to go.
We used public transport too and again so child friendly. A tip I got before we went was to buy or borrow a cheap stroller, which we did; even tho DC was out of the buggy at home, they were more than happy to jump in during long walks, or even city crowds got a bit much. Meant we could see and do a lot more, they napped in it etc