Cruise Hacks

Be sure to take a light-sensing nightlight along to not disturb your cabin-mates in your cramped quarters - you may never turn on the light switch!
Bring along a carabiner or two to get things off the floor.
Since you're packing heavy, bring an extra wadded up duffle back to bring home souvenirs above the 50 lb. limit imposed by most airlines.
Especially for a one-way trip, book your own flights and allow an extra day around your cruise on either end. Hotwire a hotel and car in each location. That way, you are eligible for bumps both ways, and you can actually explore the first/last cities in your cruise.