You might never find actual travel details on persons leaving that early. But you could include information about the USUAL type of travel that emigrating Norwegians took during that time period. Perhaps pictures of the type(s) of ships available, a possible/probable route, etc.
Such info can probably be found in the many articles and stories here - http://www.norwayheritage.com/
(P.S. Your newlywed couple appears in Hjartdal church book "Utflytte" section on the same day you say they married. That might only mean that they got attestation from the minister that day and were leaving very soon. My great-great grandfather had one of those and it attests to his birthdate, birthplace, confirmation date and place and generally confirms that he is a Lutheran church member in good standing and an upright young man and it was folded and sealed with wax. That old Hjartdal document was unexpectedly produced by a cousin long after I was convinced I had "finished" that ancestor's complete story.)