Mellow Hills is the first place the Overlord visits, while searching for the Tower Heart, which is found in the southern part of the region in the middle of a pumpkin field. It is inhabited by the villagers of Spree, and the Halflings, the constant harassers of Spree. The halflings live in their own houses near the kitchen of their King Melvin Underbelly.
To the east, there is a Slave Camp where the crane can be found. The Halfling Homes also lie to the east, where you find the food stolen from Spree. You can decide to give it to the starving citizens of Spree, or keep it to feed your minions, although the latter will give you some Corruption (+2%) and fifty brown life force immediately, the former will spawn more sheep in the pasture nearest the tower gate, granting six extra brown life force each reload(12 if you have the harvesting helm).
To the west there Spree's remaining fields, a sheep corral (containing some aggressive Rams), the Steel Smelter for your tower (which is only accessible after obtaining Red Minions) and the Evernight Forest, which is also only accessible after obtaining the Reds.
If you save the scarecrow man in the mellow hills abyss there will be crates that respawn near the start of mellow hills that have an extremely high chance to drop decent minion gear.
Points of Interest
Behind the scenes
If you save the scarecrow in the mellow hills abyss he will give you minion equipment(barrels with a extremely high chance of giving it) at his house every time you come back to the area useful for early game.