Ingrid's apartment is in the perfect location to walk anywhere you, as a tourist, might wanna go. Even if you decide to go somewhere else completely, say Sintra, the train station is but a 5 minute walk away. Even though Ingrid herself wasn't there she organized for a friend of hers to let me in and he gave me some invaluable tips.
The room itself is small and even as a couple I wouldn't recommend it for two people but for one lone traveler it is the best thing!