The sorrowing meadows introduces a few new enemies, most notably zombies but the Necromancers are tough because they can only be attacked by using Fidget's abilities. I completed a second mansion & then exited the map to revisit some of the earlier locations like the Glade & Abadis Forest to reach areas with my new climb ability.
That was all I had time for this weekend, I will continue to revisit the earlier locations like the Caverns & Hidden Cove to see if I can complete those areas before returning to The Sorrowing Meadows to visit the remaining two mansions.