Even if someone hasn’t been living in a property that is zoned as single family private residential property, SFPRP for short, doesn’t mean it still isn’t SFPRP. It’s the zoning of the property that’s important, not whether there is someone living there.
A house that is for sale and is zoned as SFPRP is still an ineligible location, even if there is something on the property that may meet criteria.
If seems that you may be in an area that has a low-density of Wayspots, too, and this thread may be helpful in finding POIs to possibly nominate: Tips for Rural Nominators