To occupy the cockpit jumpseat you would need to be in CASS however to simply ride int he back all you need is the usual stuff and an open seat....I just rode them last week and they always treat me well as an offline guy.
Like most airlines out there the NWA pilot group have been great with their jumpseats. CASS was down for a couple of hours last month and the gate agent was not going to get me on (she was working by herself on a very busy day). A non-rev NWA pilot (I assume he was a non-rev) saw what was happening, on his way down told the Captain what was going on upstairs. He came up and politely asked the gate agent if she had a spare second to hand him a jumpseat slip so he could sign it there for her. 5 minutes later I was in a first class seat back to DTW. Great guys. Thank you.