Having had a look at on OS map, I'm less sure of the access issue above. The track is on OSM but not the OS so the owner of the land may have stuck the fence up to prevent folk short cutting, though since the short cut winds up at a Bison enclosure I'm not sure it was time well spent.
You can see where it goes wrong at about 8.5k, https://www.strava.com/activities/1812309999
probably its probably right that I didn't climb over any fences and I'm willing to give them the benefit of the dbout but there is a bit of path from the opposite side and it would have saved a lot of walking.
As for the Pitcastle estate there are a power of paths marked on the OS map which I'm assuming they'd rather people didn't access. Is there someone this can be reported to? I don't suppose it makes any real difference but you never know.
For the record I was heading for Loch Derculich, very glad I didn't bother bringing my camera.