Communications via SMS was really easy and Sarka gave a lot of helpful advice for getting from the airport.

The apartment block is quiet and the main front door secure.
There is a little fridge (for beer) and tiny kitchenette - I didn't use it. There is a supermarket very close (google "Albert") and several nice pubs with great food close by.

The room is very comfortable as was the bed. I'm a non-smoker and the room had no hint of smoke. The flat was very clean and there was lots of spear bedding should you visit in the winter.
The shower was hot and clean. best of all the Wi-Fi was fast and if you youtube for music you'll be fine.

Please note: If you have small children - be aware that the toilet is in a separate room outside one door along in the hall. It didn't bother me as i was travelling alone; but with a child this would have been a hassle.

Getting about:
You're in the middle of some very nice parks and walking to Karlin is fast using the tunnel. Some nice places to eat over there too.
You can walk to the train station should you want to catch an early train but you're fr enough away so you don't hear them.

I didn't use the sofa to even sit on so can't comment on that. You're in Prague - Have a shower, get down the pub!