Hello from Sept 2024
This issue still is a problem till this day after all updates larian hasnt solved anything. After everything i had to do, and like 5 hours of my time troubleshooting, it was the most stupid solution that solved it.
I found the save file in which i could still leave and then i refrenced it to the last save file where I couldn't and there was a glaring difference that I didn't see before. Make sure all mods, settings, and everything that could change how your game looks and is played is the same. From point a to b dont remove any mods. The game save files thrive on consistency and anything you do to it can mess up the way things are loaded. If you didnt have a mod before leaving rivington for the last time, dont install it or your game might not want to load back. One of the mods i had deleted because it was causing issues months ago was the culprit. All i had to do was reinstall that gross mod and boom, I was able to get back to wyrm rock. I guess because they want to make sure npc's stay dead, the game doesn't load past areas on just a seprate file, and instead relies extra heavy on the smallest details to keep the immersion(idfk). Anyways, i guess its the same with those npc issue cuz the game has to recognize theyre dead in the first place to allow you to continue.
Nevertheless i wish everyone else with this issue finds their "missing file/object death" as quick as I did and doesnt have to restart 3 or 4 months worth of playtime like i almost had to do.
GL to the next poor unsuspecting vicitm of basketfullofequipment and the npc with 2+ health.
Made an account just to say thank you, thank you so much. I was losing my mind with this. I had the 100% version of the bug and the first thing I tried before desperately reading endless threads on forums was to remove all of my mods. It never crossed my mind that the solution would be to reinstall a mod back into the game. So leaving this here in case it might help someone else too.
Reading your comment I realized I had spawned two freaking benches at camp before entering the Lower City with the Sit happens mod, and then removed the mod a while later. I put the mod back in and I was able to travel between areas with no crash. As it turns out, tthe mod includes a spell to remove all the spawned objects and you're supposed to do that before removing the mod, so that was my mistake. Anyway, used the spell, removed the mod again, everything works. So thankful I don't have to lose hours and hours of progress (and more of my sanity).