I couldn't recommend Isabel's apartment more.
The location is perfect - a close walk to trendy bars and restaurants, but also very quiet in the evenings.
We only used public transport to get to Sintra and Belem, we could walk everywhere else it was so central.
Isabel was fantastic - we arrived late, and yet she was still waiting and made us feel at home immediately. We enjoyed the extra treats, and everything was immaculately clean, and cosy! Isabel's directions from the apartment from the airport were so thorough and she kept in touch throughout the week with great suggestions for restaurants/bars and to check how we were.
Isabel's is by far the best air bnb I've stayed in, and I hope to return!