So, I'm in Saradush and popped back to the old pocket plane to unload some goodies and get Cespenar to enhance some of aforementioned goodies. Once all was said and done, I tried to head out again yet every time I try and leave the Pocket Plane the game crashes as it is trying to load the new area (Saradush)
I have already tried re-installing BGII which cleared out all the mods I was using, but the game still crashes. I am, pretty much out of my depth when it comes to looking for scripting errors in the game codes.
Any thoughts?

I tried loading an earlier save, entered the pocket plane and then exited successfully. So I began to wonder if it had something to do with where I was the first time. So, out of vexed curiosity I loaded up the earlier save, went into the bar to where I was when I entered the Pocket Plane previously and did the same. Then, when I tried to leave, I left! No crash, nothing. So thinking I had somehow fixed the glitch, I tried my main save again, and again, it crashed on exiting the plane.
so, here is what I know.
It isn't a mod, for even with all mods removed the game still crashes trying to leave the Pocket Plane
It isn't based upon where I was in Saradush, as recreating the departure doesn't recreate the problem.
It seems to be, that ONE particular game save, but I have no idea why

I had a similar problem in BG1 (uses the same engine, so it might be applicable here). What my research into the problem revealed was:

1) It could be a corrupt save file
2) For some freakish reason, possessing certain items may cause the game to crash randomly
3) A variable or memory problem may have existed in the previous game, thereby making a corrupt save file (it continues to load a bad variable)

Those are my thoughts. I think it's likely that you'll never find a fix for the glitch. I didn't for mine.

Well crap. in between that save and an earlier is a couple hours of tedious sorting and crafting that I was hoping I'd not have to do again. Maybe I should dump all the excess gear from my pack bit by bit and see if it wont let me out after I dump item-x
...but that sounds just as tedious
crap

You could try and use the move area command to get out of the pocket plane, then go pack to it and see if it still crashes upon exit.

In order to use the MoveArea command you need to enable debug mode by opening baldur.ini file in your BG2 main directory and put Debug Mode=1 somewhere under the [Program Options] header.

Once you're in the game, press CTRL + SPACE to activate the console.
The command is:
CLUAConsole:MoveToArea("Area Reference Number Goes Here")

And here are some area codes you could try:
saradush AR5000
yaga sura's cave AR5201

So try using the command CLUAConsole:MoveToArea("AR5000") to get to saradush, then go back to the pocket plane and see of that fixes the problem.