Possible Clues:

• You plan detour that includes hilly area
• Hilltop plot covered in mud? Not at first
• High-elevation area
• Superior map produced by duke to show type of territory
• Possibly fell and died after united plot
• High elevation area
• Elevated region
• You finally arranged to forsake Northumberland moors?
• Odd bits of Urdu on edges of map identifying hills
• Hill upsetting me? Not Damon, initially