Ive heard good reviews of the Posada del las Aguilas.
http://www.posadadelasaguilas.com.ar/
As far as I can tell, not luxury accomodations but more of a country-inn style. They seem to have been doing quite well as they now get some airline business (I see their vans picking up pilots and FAs from time to time).
Let me caution you about your domestic departure.... if you are going to Trelew... are you sure your domestic flight leaves from EZE and not from AEP? If you leave from the city airport, then dont stay in EZE, it doesnt make much sense.