Weird! I've left it run for 5-10 minutes before. Guess I'll just let it go and see what happens. Will report back what (if anything) happens.
EDIT: You were right. It took 4 minutes to load this time. Then I made a new save to test and it loaded pretty quickly afterwards.

Thanks guys, sorry for ...

I've been having this issue for a while now, I probably should have reported it earlier. What prompted me was I noticed in the .27 patch notes that:
Fixed unloadable save related to underground belts in a weird state. I was hoping this resolved my issue but turns out that bug was ghost related.

I ...

Thank you, very much appreciated! I will look into my potential memory issues.

I've been playing this save all day. Had a few crashes (usually my OS locks up); when I tried to load the save after the 3rd crash within 15 minutes or so, the save would no longer load properly. I tried the previous save, no luck. I tried loading with no mods, no luck as well. Only mods I was using ...