Ensure you have a clean fuel supply
Maintain the engine cranking battery and circuit in tiptop condition
Upgrade the house electrical system for off-the grid cruising
Run a capacity test on older batteries to make sure they will hold up for the length of the cruise
Inspect, service and beef up as necessary the steering gear and autopilot
Close up any water entry points and reinforce windows and portlights as necessary
Inspect and “exercise” all through-hulls, seacocks and attached hoses
Clean the bilges, ensure bilge pumps are in good working order, and install a damage control pump
Have at least two fresh water tanks and a spare water pump; switch tanks when half empty
Ensure the navigational electronics are fully protected from the weather and any water ingress; carry back-ups
Tie down or otherwise secure all loose objects with special attention to batteries, dinghies and outboard motor gasoline tanks
Service all safety gear and ensure it is accessible