Looking for a friendly place to lay my head in Lisbon

Description

I am hoping to come and do an intensive Portuguese language course for a month before the year's end. I have visited Lisbon before for short stays of a few days and loved it, and now my two kids are in college so I can spread my wings a little and I'd like to explore the city in a more leisurely and comprehensive way. I don't have strong feelings about what part of the city, or what type of housing I would be comfortable in, with the exception of preferring a home that people haven't been smoking in. As a self-employed person, my time is my own so I am hoping to spend a whole month. I would be content with a house-sitting arrangement, or a short-term furnished rental, or a private room in a house. I repair rare books for collectors and libraries so I mix being a creative person with being very tidy and responsible. I specialize in 19th century publisher's cloth bindings, which is a small niche in terms of form (a post-Industrial Revolution structure so very standardized in format and materials) but wide open and fascinating in terms of content. I am constantly amazed by the things I learn by talking with my clients about their books. In my free time, I recently became a passionate student of drumming, which is the most inconvenient hobby possible. I like both cats and dogs, and if I have explicit instructions regarding watering schedules, I can also take care of plants.