I flew a few 12-hour missions back in the 80's in my consultant days. The plane does have a head, and bunks. Good thing, too. I'm told they chase hurricanes with them now.
Add the 2 hour preflight and a 2 hour postflight/debrief, you’re looking at a looong day. During the 80’s I was driving past VX-1 spaces at Pax River when I saw a P-3 with a black square painted on the fuselage above the cockpit. Had some dents around it. Word was that that the feasibility for inflight refueling was being tested. Ruined my day. Also at Pax in the 80’s and before, VX(N)-8 was flying hurricanes in a P-3.