This apartment is really well located for exploring Havana Vieja (5min walk), a stroll along the Malecon (5mins), several restaurants, and plenty of cabs to other parts of the city. Mirian was a great host. She communicated extensively in advance, and arranged cabs from the airport (CUC$30). Check-in was smooth and straightforward. The apartment is quite comfortable and better than the pictures suggest. The bed is a bit hard and the neighbours can be a little noisy, so take earplugs if you're a light sleeper. The aircon and fan kept us cool, and the fridge was kept stocked with beer (CUC$2) and water (CUC$1). Mirian arrived promptly to prepare a filling breakfast each morning at a time we chose, providing lots of fruit, bread, omelette and vegetable, plus fresh juice and coffee (all for only CUC$5). She also did laundry for us, kept the apartment clean (with sheets and towels changed), and was generally really helpful and kind, even turning up to greet us when we returned to Havana, and seeing us off when we finally went home. Although Marian speaks only a little English, and we spoke virtually no Spanish, we always managed to muddle through with a little help from a translation app. I strongly recommend this casa particular and would be happy to stay here again!
Marian can also arrange onward transportation to other cities and other places to stay - we had a final night in Havana but her place was booked up. My strong advice on transportation between cities would always be to take the Viazul bus, rather than the taxi collectivo that Marian can arrange - the bus is very comfortable and air conditioned, whereas the collective taxi was over-crowded, uncomfortable and extremely hot (and they are the same price - only the TC is door-to-door, but if you can afford it, the comfort with the bus is so worth it). Similarly, the room in another family's house, opposite Marian's apartment, that she seems to use as an "overflow" is substantially less comfortable and well-equipped, despite being the same price.