After climbing the windmill you will see a woman hanged at a set of barns. 
Walk upstairs to the top of that barn. Follow the walkway until you are facing 
towards the west to find a Kilroy on the wall.
Go downstairs inside the manor house, and enter the garden. Continue until you 
encounter a machine gunner shooting on the ground floor, to your left as you 
exit the doorway. Turn to the right to find a Kilroy on the wall.
After the intermission sequence showing you crossing the river to reach the 
bridge, look to the left to see two parked cars and a few upturned rowboats. 
Go to the rowboats, and look at the wall next to them to find a Kilroy .