We have a day and a half before an early flight out the following day. Suggestions on where to stay?
Go to Booking.com and use the map feature and find a place fairly close to Jelačić Square, the huge main town square that is a bustle of activity. You need not stay directly adjacent to the square. Zagreb has good tram service to get you to the square from adjacent areas. Years ago, I stayed at the Westin (I used points) which was about a 15 minute walk to the square - or an easy tram ride. Walking was easy and safe enough.
We were in Zagreb this past summer and stayed at the Palace Hotel. Easy walk into the main part of the city. Across the street from one of the parks. Good value and great breakfast. We walked everywhere. The Dubrovnik Hotel was our second choice. We booked through booking.com.