The post office is on E. Main St. in Marlton. Kings Grant is in Evesham Township but not Marlton proper.
Marlton:
https://www.google.com/maps/place/Ma...!4d-74.9218324
Evesham Township:
https://www.google.com/maps/place/Ev...!4d-74.8857989
You have the choice of Comcast or Verizon Fios for internet/cable.
Marlton ShopRite is the closest, but there are several others a reasonable distance away in Cherry Hill, Medford, and Berlin. I shopped at all of them depending on the other stops I intended to make that day.
There's also Aldi on Rt. 70 and Rastelli Market Fresh (expensive) on Rt. 73. Target isn't far from Rastelli. Produce Junction on Rt. 70 has great prices. They don't always have what you want, and some items are only sold by the bag or in bunches. It's still worth a stop if you're near.
How long have you been out of the States?