Good guide.
I've completed way more than 100 jobs on my current savefile and I still get jobs from all 4 farmers (already bought the farm). Thing is, the farmers seem to be a bit picky and won't offer jobs on all the fields. My Victora Adams for example has never given me a job on the huge field right next to her farm. So if I were to buy all fields from her, even leaving the mentioned field untouched, I wouldn't get any more jobs from her.
Regarding Job Hopper... has any digital version owner tried getting it on the DLC map Green Valley (Grünes Tal)? Maybe it's a map glitch rather than a game glitch per se. I've contacted the developers and am waiting for an answer. Since I honestly enjoy this game I might get the DLC anyway, landscape looks pretty good.