The best way to enjoy Manhattan is from Brooklyn. Transmitter Park offers views without the crowds, and you can pick up coffee-to-go and treats from nearby Ovenly. The India St/Greenpoint Ferry is a 5 minute walk and will take you all the way to the Rockaways in the Summertime.

An awesome, and sometimes free, ferry that links Manhattan at the Financial District to Ikea in Brooklyn via Red Hook. Very great views of the city and if you end up having to pay it's redeemable for a monetary discount towards an Ikea purchase. I think of it as a treat and an investment.

Home of Casa Bosques chocolates, to purchase directly at the studio.  By appointment only. 

This botanical garden is massive. If you like to be surrounded by foliage, bring a picnic on a nice day.

For brunch, the classic dish to get is the Feijoada, but the benny is also solid (and i don't recommend a benny lightly)—you can also ask for ham and spinach together (my favorite). For dinner you can also get the same thing, or the Moqueca (shrimp stew) is incredible. Pro-tip: if you're there for breakfast on a weekday, ask for a egg and cheese (add bacon or ham or avocado) on a croissant. Not on the menu—sounds basic, tastes amazing.