You might enjoy the bars while you're in Gubeng, and if you want to see some more of the larger Surabaya area, you can catch a ride on the metro at Ngagel Station.
Even though there aren't top sights in Waru, you can explore the larger area and take in top sights like City of Tomorrow. Jump on the metro at Waru Station to see more of the city.
While visiting Klojen, you might make a stop by sights like MOG Mall Olympic Garden and Alun-Alun Kota.
While Genteng might not have many sights to explore, venturing just a little farther will lead you to top things to see and do like Tunjungan Plaza and Surabaya Plaza Shopping Mall.
You'll enjoy the museums and theme parks in Oro Oro Ombo. You might want to make time for a stop at Batu Night Spectacular or Batu Secret Zoo.