Gregory's place is just as stated. It's a few blocks from the express line, so we got to Central Park and Times Square in about 20 minutes. As a female, I had another friend with me. The neighborhood isn't bad, but as a female walking at night, just make sure you have a friend.
The place had all the amenities we needed. Gregory is great and gave us directions the first night, so we knew to take the A line because Google maps would never tell us about it.
We didn't venture out much into Harlem, but there's a lot around you. There's a fruit stand a few blocks down, Manhattanville coffee which is always packed, but good, there's a liquor store right at the corner, Dunkin Donuts, Walgreens, so you have all that you need within walking distance at a much more affordable price. Because the subway is so quick there's no issue.
Enjoy your stay!