Side note: if you don't have access to ancient fruit and have trouble chasing the returns on starfruit wine, aging cheese is also a pretty solid way to go.
They have access to the island, so have access to pineapples, the new 3rd most expensive fruit in the game. 350 versus 450 base value for ancient fruit isn't bad.
In general, process all your crops in kegs or preserve jars (kegs are usually better for fruit, jars are usually better for vegetables). This will double or triple your income from crops.
See, I don't see this part quite the same way. It's not quite that fruit are good for wine, vegetables for pickles. The way this
is true is that you can't age the juice you get from veggies in a keg, like you can for the wine you get from fruit in a keg. The thing is, however, you can only age so much. In every save I will eventually produce so much wine that I could never age it all. What's the difference if I make juice and don't age it? What I do is look at the numbers.
Keg, 1 week to process, value: base cost x3
Jar, 3 days to process, value: base cost x2 + 50
The thing is, preserves jars pop twice as often... so in 1 weeks time, you're actually getting over 2x (base cost x2 +50), or base cost x4 +100 (and you've already started on next week's production).
A keg can never catch up to that except by aging what it produces, doubling the x3 to a x6... but your cellar is only so big. If you want to reach every cask, the maximum you can fit down there is 125. That means that every 2 months you only need 125 bottles of wine to fill your cellar. 8 weeks or production to produce 125 bottles? 16 kegs working non-stop will get you all you need to fill the cellar... and everything else will get you more gold in a preserves jar.