I remember boarding houses while growing up in my hometown. They were very common in the 40s and 50s (and long before that, but I wasn't around back then). There's would be a small sign either in a front window or in front of the house "Room and Board" or "Rooms for Rent". They sort of faded out, at least outwardly, over time, and I'm kind of thinking that when there were an abundance of them, it was at a time when widow ladies didn't have any (or very little) income and opened up their homes to boarders so that they could keep their homes and support their children. There were a lot of mines up there, and when men were killed or disabled in mining accidents, the family income stopped. Occasionally, the mining companies would pay a settlement to the widows when there were "special circumstances", but that happened only rarely.
As time went on and more women had enough SS benefits on their husbands' records or had worked themselves and had pensions/their own SS benefits, so taking in boarders was no longer a necessity.
Seems to me that there would certainly be a market for boarding houses, especially as the population ages. Me? I'd rather have a room and meals in a boarding house than be totally alone and without anybody at all for company. Kids grow up and leave home, one parent dies, the family home becomes too much for the other parent to keep up and hiring help too costly, kids ask the age-old question"What are we going to do about Mom/Dad?" because they live too far away to help. A good solution for all. Mom or Dad isn't alone, kids carry on with their lives knowing that if the parent gets sick, there's at least someone to let them know.
Maybe it's an idea whose time has come again. A good alternative to living alone, being uprooted and moved to be closer to their children (and leaving behind their friends and a place that's been home) or being parked in an assisted living facility.
Kaya, I like your set up a lot. And I love, love, love your back yard! How pleasant and serene.