So I visited the Upper East Side with my wife and 14 year old daughter for Christmas week.
The keys are located in a lock box a couple of hundred yards away. You will not be given the exact address till 24 hrs before you arrive, I'll leave it to Jeff to explain why.
The apartment itself is basic but comfortable but for me far better than 2 hotel rooms as you get a lounge and small kitchen too.
One think to note there is mention of a laundry area on the premises description, I was disappointed to find there is no laundry area/washing machine.
If you want to watch TV you will need TV app subscriptions.
The location of the apartment is excellent on a quiet street. Central Park is 15 minutes walk and the East River 10 minutes.
The area is overflowing with great restaurants and bars.
The subway is 5 minutes walk away, generally about 20 minutes to Times Square.
Overall, I would absolutely recommend Jeff's place, I hope he doesn't mind my brutally honest review!!