Depends on one's goals. I think I am following the way of the Lazy Farmer, probably closer to a Lew Zealand farm than yours.

In the long term I don't expect to do much other than the greenhouse, so just a ton of kegs for the ancient fruit (and daily cherry, orange, peach, pomegranate, and apple) and a few preserves jars for the daily apricot.
Having seen a salmonberry season at high foraging skill, there's no way I'll turn those into jelly -
way too many berries, too much effort!
But yes, good point, for farmers willing to put in the effort to use vast numbers of jars (and beehives), I can see coal being a major long term problem, even more than the early game problem I've experienced.
Edit: Here's a fun thought: what if Willy needed fuel for his boat, in addition to the hull repairs, anchor replacement, and ticket stand batteries? Bring him 200 coal!

I am very glad that's not part of that quest...