Thanks for the tips, especially on pathing. I'll probably just knock it all down and build sonething new. I'm more about the building than the progression i think.
Problem with demo is you dont get the resources back... which sucks. So I feel like it's a big waste to completely demolish, just let the mobs destroy it.
For trap placements, it took me a bit to figure out the pathing tricks, and also relies on spawn points and stuff. When Its a new defense point I'll setup a basic fort with last-resort defenses inside. I'll save exterior trapping until when I'm actually defending so I can see where the spawns are and how they are pathing.
For subsequent defenses, the mobs spawn & path in the same spots so then you can build out and place more traps ahead of time.
Just try to create funnels into tunnels, and then trap up the tunnels as much as possible.
I usually do 2-3 stages:
1.) Exterior traps on random floor/walls to soften em as they approach
2.) Funnels & Tunnel systems to kill most of the enemies
3.) Last Resort defenses at the objective to hopefully catch any stragglers.
The harder defenses have TONS of enemies and you'll be building walls/traps during the defense. I believe Stonewood #10 had waves that required killing 600 enemies . Structures WILL be destroyed, don't worry too much.
To win your goal isn't to have a pretty fort at the end. You throw down walls/traps to delay/kill as much as possible