Rena's studio (DanceLAB) is at a great location. Away from the touristy part yet still central. It took me a 22 minute walk to get to Charles Bridge and about 10 minutes to the central train station. There is also a nearby metro station.
Rena's DanceLab fits right into the neighborhood: I saw two vegetarian restaurants, a yoga studio, a poetry coffee shop... And there are other bars, restaurants, beer gardens and shops nearby.
Due to floor polishing I didn't stay in the DanceLab; Rena put me up at her apartment (which is nearby). I saw the DanceLab and the bed futon, with the adjacent kitchenette and bathroom and I thought it looked perfect. I'm not sure if it is possible to sleep with an open window (something I like to do), because there are no windows in the futon area (but I think it had a skylight), however I believe there are windows in the dance studio right next to it.
I'll gladly return to Rena's on my next visit to Prague, because she was a great host who made me feel welcome and at home from the first minute. And her English is excellent.