Corn isn't very economical for the space required, and neither are most other grains.
They'd be best served growing higher yield per area crops such as potatoes, carrots, bean, tomato, pumpkin, etc. Basically what you might find in the average backyard garden.
Save the grains for later when they'd obtained a way to till larger areas.
Animals are another item that can wait to begin with, although if they do happen to come across some cows, sheep or whatever, there's no point
not grabbing them, provided they've got a secure field to put them in (and winter shelter if it's an area that would require that). That said, a small herd of goats or pigs will do wonders when it comes to clearing away weeds, and pigs have the added bonus of digging up the earth for you too.
Chickens are likewise great to have scratching around, eating pests and fertilising as they go.
Once they obtain livestock they're going to have to think about predators too, both four and two legged. Dealing with them might involve locking the animals away in a barn at night, posting sentries, or hunting potential predators (or even all three and more options).
After harvesting, vermin could become a major problem. Mice LOVE food stores, especially grains....
https://youtu.be/rAdNJ1jczVI Note that's happening now at a time when baits, electronic repellents, etc are all readily available.