We've been staying in Ana's flat for three nights and really enjoyed our time there. The apartment is small but has everything one may need. It's 20 minutes to walk from Apolonia train station where we arrived coming from Porto. Ana's friend then welcomed us in the apartment and gave us some useful tips to get around in the city. The central square Rossio is about 10 minutes walking time. From here you can explore the city and take the train to Sintra.
We can highly recommend the flat and will come back next time.