I'm currently running two separate Greyhawk games, with very small parties, one based in Sterich, the other based in Furyondy.
Both are using the Greyhawk Boxed Set, and Greyhawk: From the Ashes as the starting point. War has just ended. Sterich is free of enemies but fighting continues near the mountains, but most of it is empty and ruined. Furyondy is beginning to rebuild its defenses as the Treaty of Greyhawk settles in.
In Sterich, the party is going to go explore the Crystalmists to find out why the giants attacked Sterich. There are lots of ruined outposts/keeps and battlegrounds to traverse, as well as empty villages.
In Furyondy, a Paladin has been sent from Veluna with troops to reinforce the front against Iuz. The Paladin is currently travelling along the front between the two nations, then will likely travel across the lines into Iuz's newly taken territories to wreak some havoc.
Both are sandboxes (both also using Old School Essentials, though Sterich started in Beyond the Wall).