It seems like Fagerland is a farm name, and if they are Norwegian, would have originated on a farm named Fagerland, or any of the variations you have listed. To find farms with those names and their locations, go to the farm census of 1886 and type in just the beginning Fagerl and it will show you all the main farms and subfarms starting with that beginning.

http://www.rhd.uit.no/matrikkel.html

Perhaps they didn't move far, but just across the border into Sweden, so with a good map of Scandinavia, you can determine which area is closest and start from there.