Pension Liverados is really a beautiful pension and its very peaceful. The rooms are decorated nicely and kept clean. I stayed 2 nights and had a room for one person. The room size was spacious with a double bed. It also had fridge, good wifi strength and nice balcony. Anna and her father are very friendly and helpful. The location in Karterados is good because you can easily catch bus to Fira, the port, or anywhere else after walking a short distance to bus stop. (It's possible to walk to Fira but I wouldn't suggest it if it's very hot.) Buses come every 15-20 minutes for Fira. There is also a mini-market very nearby. Airport pick up late at night was very helpful!
Only downside is that bathroom is small but I've noticed that is the case for all bathrooms in single person rooms in Greece. It is a bit tight but manageable as long as you are not very large. In addition, you have to hold the showerhead because there is no hook to hang it from.
I would stay there again.