NYC is a beautiful city, probably my favorite. You will surely enjoy it
Some things that I can share from my travel experience to there:
1. You don't need cash, a CC or debit card will work without issues.
Depending on your bank you must notify them of your travel, so they "lower" the security
requirements for the transactions. A lot of credit card terminals in US are still using
the magnetic band and that could cause transactions being rejected. (Happened to me)
When paying in a restaurant for example, you need to add the amount of the tip
to the receipt AFTER you paid with your CC or debit card. You will leave the place and
if you check your bank app, only the the meal has been charged. A few days later the
charged amount will increase to reflect the tip. Really crazy if you ask me.
2. I asume that you will be visiting the Statue of Liberty, Empire State, etc.
If possible, always purchase the "express" or "VIP" tickets. They are a little more expensive
but they will save you HOURS of waiting in a line. Time that you can spend enjoying the city.
For the Empire State for example, they cost us $30 over the regular price, but we got
up to the top in 20 minutes.
Purchase over internet only. Avoid any street seller, they are everywhere and they
are really pushing. Lot of them will lie about ticket kiosks being closed or something else.
3. It's a big city. It seems smaller in the map but it takes a lot of time to move up and down.
Use the NYC metro. When planning your day, remember that a trip from Wall Street area to
central park needs 50 minutes at least for example. Cars, taxis are not an efficient way to
move around the city. Use UBER to go from the airport to the hotel.
Not sure what you had planned for internet access, but an ESIM (like Airalo or GigSky),
it's my favorite solution. You can keep your SIM in your phone and add the internet access
with the virtual one. Apple Maps do a great job with the Metro, showing detailed instructions
to stations and train numbers together with time schedules.
4. Food is expensive and you have to tip. A 2 course meal in a regular restaurant would cost you
over $100. Without wine. In Little Italy expect to pay around $80 for 2 course pasta meal.
Also, there's not such a thing like American food. Most of the food that you can eat in NYC is Italian,
Mexican, Chinese, French. Unless you are foodie and expect to invest lot of money eating (like $400
or more for a 2 course), the quality of the food are not worth the price.
There are numerous Deli's where you can taste a more traditional food and eat on a budget.
Places like Paris Baguette are great to enjoy a delicious breakfast.
5. Shopping takes lot of time and effort. Stores are gigantic. You can easily spend 6-7 hours just
in Macy's. Plan ahead.
6. Use the Ferry's. They are several of them and it's a fantastic way to see the city skyline.
For example, after we crossed on foot the Brooklyn Bridge, we returned to Manhattan in a Ferry.
They are ridiculous cheap as well.