Help with modding a mod

[RobinHood70]

I need some help in modifying a pre-existing mod (namely the UOP). I've read the De-Isolation Tutorial on TESCS Wiki, but it didn't really seem to address what I'm trying to do, or when it did, what it told me to do didn't work in some cases. So let me start with a real-life example, and hopefully someone can tell me how to do this.

In BravilWorld, BravilSouth01, just at the top of the dock steps, there's a broken path node (two of the nodes aren't linked). What I'd like to do is link those two nodes, but based on the modified grid in the UOP instead of the base grid in unmodified Oblivion. Seems simple: load them up, make the change, save. Except that the "save" part is invariably preceded by a different step: crash.

So how do I go about making my own ESP using the UOP as a base over top of Oblivion.esm? No matter what I try, it crashes.

I tried a Merge to Master using TES4Gecko, thinking to fool TESCS into thinking I was using a single Master file, but that runs out of memory without completing the operation.

Obviously this must be possible somehow, since other patches modify the various DLCs, but for me, these too also usually or always crash.

What am I doing wrong, or not understanding?

[shadowchao]

Just do it separately and load it after?