We stayed at the Condado Plaza before a cruise last spring. Very nice hotel, beautiful ocean views, a really nice pool area, and easy access to a beach within the breakwater. It was very close to Old San Juan (we used Uber, not sure it would be easily walked?), and super close to the cruise port. I feel like the airport was about a 20 minute Uber?
It wasn't terribly expensive (I feel like it was about $250/night) for 4 of us in an oceanfront room with a balcony. The room was quite large - plenty of room for 2 adults and 2 teens.
I'm not sure about food in the area - there was a Starbucks right there, but otherwise we ate in Old San Juan.