The issue I faced when I started was the dog boarding at the same time as humans. I dealt with that by having baby gates in the house/leaving dogs outside/only having airguests when I could be home. Then I retired, then I added onto my home and put a lock on a door between their space and mine.
As for the rest of the space…it’s a new addition that is permitted and up to code. It’s about 200 sq ft total attached to a single story home. There are no stairs or basement. The electric in the bathroom is GFI. There’s no handrails but there’s also no tub. There is a private entrance for exit in case of fire. If somehow the fire was blocking the front door there’s the front window and if I’m home, the door into my home through which we could exit. Everything is plugged in to an outlet there are no extension cords running to and fro under furniture or rugs. I have the window AC on it’s own circuit. There is a small refrigerator and microwave but no cooktop/hotplate/toaster/oven. There is a direct wired CO/smoke detector installed.
There is a small desk lamp that operates on battery if there is a power outage. I live in an area that has few natural disasters so a go bag isn’t necessary. I don’t allow children and if someone writes to ask about it anyway I’m strongly discouraging.
I do have a space heater in the winter, an iron, a blow dryer and an extension cord available for guest use. I’m not going to inconvenience 99.9999% of guests on the off chance that there will be an accident. I’m not going to cut down the healthy tree that is 3 ft from the house on the off chance that it could topple onto the home. I should have cut it down to add another foot or two onto my front addition but that’s a different story.
I can’t think of anything else that it would be reasonable for me to do.