I am here to quibble, seems I lost 5 points. So I am challenging my score, for a bit more credit.
Here is the final navmesh for my external farm area. Nothing wrong with it in that picture, CK passed it and finalized it. There is a glitch you cannot see, but I do not think I should be deducted for it. The chickens on the 4th attempt to get rid of a CK glitch, lost their separate navmesh. The CK passed and finalized all 4 attempts. The tiny island on the road was always there, I sank it.
Final navmesh for the shack area, to more clearly see there are NO islands, and no overlap, it got a bit squished, after my bad experience with the farm house navmesh, I was attempting to fit everything in and delete nothing. Which is ridiculous and impractical, but I wanted no more glitches. Two triangles were deleted because the CK complained about them, I redid them exactly the same, it was happy. This is the updated version, only difference is I got rid of the post in the shack, added a seat by the fire, and landscaped near the workbench so I could join the navemesh up on that side and followers could go all the way around the hut. The drop originally there meant they could not pass on that side of the shack. I deleted no part of the navmesh making those changes. That area was never an island, the ramp worked just fine, followers could eventually get up the bit of drop that was originally there, but I put the ramp in anyway, to save them the struggle.
My original version that seems to have started all this, just so no one can say I altered anything to get rid of any islands or overlaps.
And just in case i lose points for the clean table.
And I navmeshed around the bucket of fish on the pier, because the bucket is static. Did not want anyone to kick the bucket and fall off the pier.