Better Cities would have been absolutely lovely, giving me a lovely change in general scenery for my new experience with Oblivion on PC. I played Oblivion to death on the Xbox and it's nice to see different things for once.

Alas, it cannot be.
Better Cities worked pretty much everywhere... unless it was related to the Imperial City. Not only is the interior map incredibly clunky (Forcing me to find the outside "city isle" before letting me fast travel anywhere), it's also the main source of CTD's. Even when I tried doing the aqueduct quest, I'd CTD every time I tried fast travelling near the objective.

Disabling does not help, since it seems to be the primary cause of a common glitch that removes interior doors half the time. Usually "coc Testinghall" opens an area where I can leave and fast travel around, it's still a major pain in the ass.
I'm wondering how I can remove Better Cities in its entirety - including all of the "Primary Resources".

I wish I could get it to work but as it is... I'd rather it just be erased from my computer entirely. (Unless someone knows of an easy or simple fix).

What you describe is not caused by Better Cities. BC does not disable any interior doors, and I have never heard this common glitch you refer to. Also BC IC does not cause crashes, so something else in your install must be the cause. A recent release of Oblivion Reloaded was the source of frequent crashes for me, so if you're using OR try downgrading to an earlier version.

to uninstall BC completely, follow whichever install method you originally used, but in reverse. So if using OBMM or TMM, deactivate the OMODs; if using Wrye Bash, right-click each archive and select Uninstall; if using NMM, I'm not entirely sure, but presumably select each archive and there'll be a disable/uninstall option on the left; if installed manually, then you will need to manually find and delete each file you originally installed, following the manual installation instructions and remembering which options you chose originally.

I used NMM. It can disable mods but it doesn't really "erase" them.

And I figure it's BC because this glitch never happens when the mod is active, but BC makes my game more unstable.

You claim it's not the problem, but I'm just seeing a common denominator. I don't run a lot of extra stuff, mostly clothing, a companion, Kvatch Rebuilt, and some other assorted stuff.

The common denominator in this case is the user.

Better Cities is one of the best maintained, constantly improved mods out there. It works.

You might have better results asking for help rather than starting a thread that badmouths a good mod. And the person who is kindly interacting with you to try to help is one of the mod creators.

And I do suppose you could use some help, considering that you don't know for sure what operating system your computer runs and you don't know how to open a pdf.

First of all, get Wrye Bash, it's the thing to use for Oblivion.

if you use bash to install BC you can then use it to rip it out again (even if it was installed previously).

Beyond that - we would need a full mod list - and a fuller explanation of "removes interior doors" with examples.

I suppose it's possible that a funny setting in BC could do that, given that every interior has two accesses to the outside world - one for BC and one for OBC.

Since you installed using NMM, I do not know this tool very well so cannot say for certain that it does a proper job of uninstalling any mod or whether it might leave files behind. Follow the manual installation instructions, and each time they tell you to copy any file or folder into the Data folder, look for that file (and if a folder, then look for every single file from that folder as found in our archives) in your Data folder.

You refer to the other cities which have two accesses, one for closed and one for open. Zydrate stated that doors were removed in the Imperial City interiors, the Imperial City does not have open content, so BC does not touch vanilla doors to interiors for the Imperial City. As BC does not touch vanilla interior doors, I do not see how it could relate in any way to BC. Zydrate would need to prove a link between BC and the issue experienced.

Zydrate also stated that Imperial City interior doors getting disabled is a common glitch, if that is so then there must be a known cause for this glitch, in which case by identifying where this common glitch has been recorded, it would be possible to find out the known cause and determine whether or not BC could trigger it. I can only advise that before Zydrate's post, I cannot recall a single report of this glitch, whether in relation to BC or not.