Punta Tombo is definitely one of the best places in the Patagonia to watch penguins. I recommend renting a car to see the penguins at Punta Tombo (it takes around 90 minutes to get there from Trelew). The reason for car hire is because tour buses go there in the middle of the day which isn't the best time to watch penguins in Punta Tombo. The penguins are much more active n the morning and late afternoon.
You can't visit such a remote part of the world and not enjoy it at your pace. I too strongly suggest renting your own car to follow your own agenda and stop along the way to see other things like the sunset.
It's such an amazing experience being able to walk among the penguins, watching them build nests, feed their chicks, etc. The best time for viewing is from September to March, though I'd go in December when the colony is full to the brim penguins.