I used a trail of AirBnBs across Scotland and Ireland for my vacation in 2020, but having your own Black Valley cottage is an experience onto itself. It helped that I came in late, it was storming, and both the rain and wind were howling around the roof and walls. Very cozy and atmospheric!
Just a word of warning though: Bring Supplies! Especially when visiting such a remote location! My schedule was off and I came in without food. It's not Margaret's and Patrick's job to take care of that (although a biscuit somewhere might've been a thoughtful touch) and I regretted not bringing my own that night as my stomach turned in on itself. Fortunately there are opportunities around during the day (Kearney's Cottage, Black Valley Lodge), but pace yourself!
Otherwise I visited during COVID-19 and the hosts are very dedicated to cleanliness and social distancing. I imagine I would've liked to visit under different circumstances, but that's a pandemic for you. Margaret and Patrick at least, do a bang up job under the circumstances and it's perfectly safe here if you're worried about that sort of thing.
Global and personal circumstances not withstanding, Margaret and Patrick as host and the stay they offer, come with my recommendations.