If you ever visit Hallingdal, they have a local archives open several hours a week (next to town civic center). I was at the archives exactly one year ago (Thursday AM), and found some helpful people (especially after we established a blood relationship). It's a pretty town with a museum up on the hillside, and the 1000-yr old Torpo church is a bus ride away.
I visited those archives in October last year, just missed you. I have the name and address of one of the seniors working as a volunteer at the archives. I also have the e-mail address to a local historian who is working on the bygdebooks for Aal. I could forward a question to him if more information was posted about the persons "missing".
Hallingdal translated is "The Halling Valley" and within that valley there are a number of small communities. As you travel through the valley you will pass them one after the other, and they have their small community centers. From the old times they were seperate church parishes.