Provisioning will depend entirely on what you and your family
or crew normally like to eat. Write down what you are now eating for each day for a week. Multiply each of those items by 2 months or more. Stock ingredients required to cook those dishes. Then fill any extra storage
areas with your 'special' items that might not be available in distant places.
I stock heavily in areas where 'home' style 'convenience' foods are available. Certain items are not available outside your home area. For us, it is dill pickles...very difficult to find in the South Pacific
For long passage: 10 jars peanut butter; 10 jars of sliced dill pickles; lots of powdered milk, flour and sugar; large can of powdered eggs (for baking only and lasts years -- save the whole fresh eggs for scrambled, etc.); huge container of pancake mix that requires adding water
only; ample supply of favorite pancake syrup (many places sell only honey--YUCK!); a dozen or so cans of various soups or stews for those times when it is too rough to cook. Also instant potatoes last a long time and come in handy to round out many types of meals
or to thicken soups when fresh potatoes are not available.
After those basics are covered then your storage
limits determine what else you want to stock. I try to keep extra bags of sugar, flour and corn meal stored away because I bake a lot. Baking powder is another item that is sometimes difficult to find, but you have to watch expiration dates. We have 2 large locker freezers on our boat. One of the convenience items for long passages that we like is rotisserie chicken. I remove the bones and skin and vacuum seal into single
meal serving sizes. So many things one can do with these.