Yes. The problem turned out not to be related to Thieve's Den.

It is a glitch in the GetSelf function when a cell is loaded as the player walks around the world (http://www.gamesas.com/index.php?/topic/1182250-getself-glitch/).

People with the Thieve's Den just happen to often walk to the Anvil docks, instead of teleporting, and this approach by foot caused the CTD.

(same answer at the Nexus, btw, so neither is left unanswered)

QQuix: Awesome, don't know why I haven't run across your stuff before. I have interest in your Anvil Docks plugin, whether any dev is coming from it that you know of? I just d/l it, and will be testing it thoroughly. My interest is in whether this could be used to reduce lags in certain NPC infested areas, seeing as you chose Anvil Docks and its laggy. Cheers and thank you for your expert effort!

Nobody asked any deep questions, so I guess nobody is using it.
Well . . . not true . . . I am using it on my Vox Populi mod (a.k.a. The Evolving Society)

I am afraid it will not improve performance, as I still use AI packages to handle NPCs.
Feel free to post questions in the http://www.gamesas.com/bgsforums/index.php?showtopic=1060697 thread if you run into problems or want to clarify the concepts used.

Very well, I will keep that link bookmarked. Thanks, and I am really glad there was a fast response. Obviously, you still have interest in your proof of concept. Expect some sort of response in the next week from me, as I will be playing in Anvil soon for quests sake (main).

erm...dam. Save game load=

** Script Error: Script 10001c85 in file "QQuix Conceptual - NPC ACE - Anvil Docks - Beta 0.1.esp" **
Too few args for format specifier

OBSE.log on load savegame. I didn't look at it yet in TES4Edit or CS to see scripts. I will get back to it tomorrow, as I have family things to take care of today.

EDIT: I get this error only if I am not in Anvil. I should have said also that I did not CTD, merely received a menu message that OBSE made a log of a script error. The game went on. It was actually less laggy in the Anvil docks area with this mod plugged in, if you can say that 18-27 fps can be smooth I would describe it as such. Without, is a jumpy 14-19.

Yes, found it.
Go to the zvRefShowState function script and, a few lines from the bottom, replace the line
let sLine := sLine + sv_construct "= = WS: %i %n " refWS
with
let sLine := sLine + sv_construct "= = WS: %i %n " refWS refWS

This error should not interfere with the mod. This function spits a lot of information about an actor to the console (AI Package Name, AI Procedure, Anim, position, etc). The faulty line adds the worldspace FormID and Name when the player is not in Tamriel or in an interior cell.

Yes, I am around. I work on my mod a couple of hours a day and I usually keep an eye on some forums.

As for the performance, this mod simplifies the AI package list as it adds a simple one at a time, but I doubt this would make any noticeable difference in performance.

Excellent, Thanks. I still haven't had time to sit down and read script line for line, but plan to do so today. As for performance, eh maybe just feels better than Vanilla