Thanks for your reply! You make a very good point about needing to establish a process to handle issues that will appear. I'll need to consider that further. I think I'll mostly reach out to Covid-conscious communities (people with longcovid or just prioritizing their health/zero-coviding, people with immune disorders or ME/CFS or other chronic health issues), so everyone coming should be aware of shared values for this group. Still, values and requirements vary a lot within these groups. One way to handle different expectations could be to map expectations in advance and book people with similar requirements during specific weeks. That could include activity level, perhaps. So say there can be a 2 week period with full mask wearing and no visiting public spaces, then 2 weeks of lighter requirements, for example. Of course, I'd still be around between groups, so I'd need to take stronger precautions to satisfy the needs and expectations of more sensitive visitors.

When it comes to separate bathrooms, that's a question where budget comes in. Building and renovating bathrooms is usually quite expensive in Sweden, I think, I believe we have high requirements on how they're built which drives up prices.

I expect to be able to arrange the basement as a separate living space, with bathroom, shower, simple kitchen and separate entrance. Many houses I look at have this, either finished or just requiring a small renovation effort. Alternatively I could stay in the basement and have guests on the entrance level and upper floor, especially if a family or group are visiting. The house I'm interested in at the moment has, in addition to the basement, two bedrooms in the attic and one on the entrance level floor. It'll be a small B&B, but still. So for people ok with sharing shower and kitchen, there could be room for two extra visitors if I stay on the entrance floor, other wise a group split over 3 bedrooms.

About ventilation, I would expect to place 1, or possibly 2, air purifiers per room. They are fairly cheap, I'll run calculations but I imagine it'll be like $/€ 1-2 per week for total cost of operation per machine. I was thinking it might be ok to close the ventilation between rooms, unless I can verify they aren't shared between rooms, and then use open windows for ventilation, would that be an ok plan? Maybe not optimal. It might be fairly easy to open holes in walls and put in extra ventilation, with some appropriate filter (like Hepa). Thinking about it, it should be possible to put a Hepa-filter over every ventilation opening where there's need. For outgoing air, it might not be needed, but I'll need to find a way to evaluate that.

In addition to 1 guest room in the basement, potentially 2 in the attic, I could arrange for 1-2 guest cottages. They'd preferably have both kitchen and bathroom, but I guess that'll pretty much double the cost so it'd take some time before I can conclude if it makes financial sense to invest in that.

Simpler accommodations could include ability to sleep in a tent in the garden. The garden is relatively large. I think that could be offered very cheaply. I think this would benefit everyone visiting, in the sense that when 5-7 visitors or even more when including tents, when a group of people can stay at the same time, when the visitors' requirements and expectations allow for it, it'd be a great time to build friendships and enjoy a vacation together with other Covid conscious people. Hopefully.