Seems our games are running similarly, mate
I opted against kiting the Portland guardians, cause they aren't that powerful anyway. I am using Scoffers, the starting 2 Demonesses (can't find any more), Demons, Demonoligists and Evil Beholders. I am getting um... re-used to the old KBAP tactic of kiting enemies into traps, as I have 4 at any point on the field, and I am not far away from a 5th. Swapping the best enemy archer unit is doing wonders too. Especially since I always try to swap them for a demon-summoned creature with a trap right behind it, lol - if you don't kill the ranged unit yourself, it will move a hex back and fall into the trap. Fun times
I haven't moved on to the other 2 islands, Inselburg and Monteville. I might do some scouting to see which ones provides better options.