The Patio is a fantastic location if you’re exploring Lisboa and surrounding areas. I took public transportation throughout and it is by far the best I have experienced. I would definitely suggest you talk to Andre for his advice as all his suggested were fantastic.
I had heard from some people (in Cascais) that Alfama may not be a safe area. That is not true. I walked around the neighborhood even late in the evening ~11pm and had no problems. I saw many females walking in the area, so that would suggest that it is not unsafe. As in any big city, common sense must be applied however.