I was working at the local Family History Center and was introduced to this wonderful resource.
According to FamilySearchWiki here is an explanation of bygdebok
Norwegians (outside of cities) lived in communities called "bygd" which really were small towns and villages. Norwegian Farm Books contain histories of these bygds, their families, and their communities. There is a surprising amount of information contained in them about families who lived in these communities, sometimes they list parishes that families have come from as well as where they move to. They have been transcribed from the original manuscripts and can be found in book form now...although they are not yet translated into English.
What is wonderful is that there is a Stange Bygdebok and a Løten Bygdebok which are the areas that I have traced the Christianson family in Norway. What is even more wonderful is that the local universities have these books. I am attempting to get them through interlibrary loan and if that doesn't work I will make some trips to get them.
I have found the Stange Bygdebok at the University of Minnesota library and the Loten Bydebok at St. Olaf.
It may take a little while to receive/view these books, but hopefully at least one will yield some good results. Guess I should have some Norwegian Language aids to help me read them. Wish me luck!
UPDATE: Unfortunately the Stange Bygdebok didn't help us in our search. It turns out that after more researching our family came to Stange from further west and unfortunately that area does not have a Bygdebok. On to Loten I guess and to St. Olaf where the the Bydebok is. They don't lend it out so it will have to be a trip when the winter weather takes a break.
