I don't know the expected sailing versus motoring time for this route, so take that into consideration. I'd take half-a-dozen fuel filters; say four primary and two secondary in case of fuel contamination or particle re-suspension which has shut down many diesels from filter clogging trying to run in lumpy conditions. Also, of course, be set up to change them out, even in low light. That brings up my usual concerns about lighting and personal torches. Each crew member should have a personal light kept with her or him at all times. If the engine compartment is not well lighted a head lamp can be useful working in there where the primary fuel filter is normally installed. For personal lights, I recommend underwater (dive) lights that you can find at dive shops in case someone unexpectedly gets drenched at night and the light gets wet. (Or, it gets dropped or soaked in some water.) For entering new anchorages at night you should have a 1,000,000 candlelight spot operable from the cockpit and the foredeck, even in rain.
I've had friends making passages where they challenged their bilge pumps just keeping up with water coming in via portlights, hatches, and cowl vents, etc., and other places on deck. I carry a large tube of silicon grease to apply to leaky seals of the portlights and hatches to stop water ingress. Also, be sure you can seal your cowl vent holes from the outside with the manufacturer's cover. Generally, in moderate to rough conditions, you should not have to open cockpit lockers to get to critical spare lines or tethers; so, they should be mounted on the rails. It helps if they are labeled for a specific function (say, preventer). Anything put on the rails, even "temporarily", should be lashed; so carry short (2 or 3-ft) lengths of lashing line that are easy to keep with you, etc. You should have an in-line pump to transfer diesel fuel from your jerry can to the diesel fill of the boat. (Rather than trying to do it the bubba way of standing up and pouring into the fill via a flimsy funnel while trying to hold on to the boat.
) Carry a couple of "multi-use" 3 to 5 gal buckets with lanyards that you can puke or piss in if required so it's not necessary to lean over the rail or go below while on watch.
I'm sure there's more, but I think you get the obvious picture here. Keep water out of the boat; keep important lines and tools, even spares, handy; and don't find yourself trying to do something important, especially if urgent as well, in poor lighting or outright darkness, etc.
