Need some help - Telemark

I have been trying to do some research on my Ggrandfather, Aslak Osmundsen. He came from Telemark, thought the Vinge/Rauland area. The LDS does not have church records on line yet for that area or time period (1820-1860. Census records are not much help because of the big time frame and knowing exactly who or where I am looking. I have been looking at the parish records on microfilm but can't really find anything definite. I think I found his brother's confirmation but no birth records for either. Since I am not familiar with that area, could someone give me some ideas of what parishes would be close that they could have either moved to or from? It seems as if they didn't stay in one place long. If there are some other websites that I could visit, I would very much appreciate that help. I believe that their fathers' name could be Osmund Knudsen. I enjoy reading this website and everyone seems so helpful. Even though it is frustrating at times, I really enjoy trying to find my relatives. Ann