Eigenk�thner :People who have permission from the Authorities to build a small houses, with a garden space on public land. -- I don't know that there is a single term in English for this.
Altsitzer: Person who has transferred his farm to his son or other person, but who still lives there. -- Again, maybe someone knows a single English word that expresses this.
What I usually do is leave the German word there, when I translate, so that people need to go to the glossary to find the meaning of a term that you can't keep repeating all the time, but which you don't want people to mistake for something it's not.
Edith