Rizzy takes level 1 maximum crypt on snow for a tower on the first day! No magic or morale!
There might be a better way, but I'll share mine, as I didn't find any screenshots or detailed descriptions in this thread, and it shouldn't just be lost.
These screenshots describe the most difficult scenario, where gremlins deal weak damage. You can use a magic arrow to help where needed, and if morale drops, you can get away with just a couple of gargoyles.
Use it to your advantage!
P.S.: For those who want to test themselves and me, I've attached a save file! :)