Huge Landscape Workflow

Hi guys, i have a question for you, i’m creating a huge landscape from world machine, the landscape have 14 square kilometers and i dont know the good workflow that i could follow for create it with a nice resolution and dont have a file with 1 giga, I created my landscape on unreal and i need to mantein my shapes (i only want to take it to WM for do more detailing) any sugestions?