John,
I would think a "minor" kit would include the parts to help you get safely back to civilization. Things that come to my mind are a transmission oil cooler, an alternator belt, spare cooler hydraulic lines, a radiator cap, starter solenoid and a spare set of coolant hoses.
My thinking is sometimes a little more basic than others- but I know from experience that starters seldom fail without warning, a stuck thermostat can be removed and injector lines seldom fail (i have never seen one fail). Valve cover gasket leaks can be dealt with till you get back to the slip.
Having said all of that, a long range cruising kit will be totally different. Getting parts in the Bahama's I am sure will be time consuming and expensive.
I am putting a "kit" together slowly for long range. It includes a spare heat exchanger, water pump and will include thermostats, oil sending units, a spare starter and some spare injectors. I have twins so I don't think I will invest in spare injector lines. Just my thoughts.