I've had good luck having -scOfflineOnly in the commandline.txt file when playing the modded story mode. I went from crashing ~20 minutes into the game to rock solid stability for 4 hours straight before I quit to do something else.
On my case, common error 0xc00000fd caused by scripts (NET crash) and 0xc0000005 caused by mods (contain large prop or hight texture) also because of gameconfig that cant handle mods and scripts running. By editing gameconfig causing memory leaking maybe that why the game running in certain time until reach memory limit and than CTD.
Game crashes are notoriously hard to track properly. A few things to keep in mind, though:
I hate the Rock* launcher like any other person, but it should not be subject to FUD. The launcher is not responsible for all sorts of weird errors ppl are experiencing (and attributing to it). Once the game is running, it doesn't mess with the game at all.
Fixing one particular item in the gameconfig does NOT mean you 'solved' it; you may have fixed one thing, but likely broke something else in the process. Tweaking gameconfig settings is simply a beatch, and highly contigent on what you're doing with your mods. And thus a very individual matter.
.NET errors may point to a script error (the .dll kind), but even that is not entirely sure. After all, SHVDN is kind of a hack (albeit it an awesome one), made to have .NET stuff run under C++. There's no telling precisely whether your own C# script went awry, or something along what makes the 'hook' work.
Memory seems still the most prominent culprit for crashes (assuming you already installed the heap adjuster and such). I can mod for hours, without a single crash, and load (Menyoo) an entire car park, and 100+ peds, and see me crash within like ten minutes. What gameconfig value needs to be increased, or decreased (!) for that matter, is always a topic of much frustration.
Use the true and trite process of elimination. Start big: rename your scripts folder. If the crashes are now gone, likely one of your .NET mods caused it. Then rename the scripts folder back, lower the granularity, as it were, and start remaming the extensions of the individual scripts, one by one, to see which one it might be.
Do the same for addon packs. Remove your car addons DLC (you did consolidate them all into 1, right?!) from the dlclist.xml file. If the game no longer crashes, or less frequent, then you need tweak gameconfig settings for that area. (Indeed vague, but there's no 1-solution-to-fit-them-all).
Okay the wonky format is working too, just tested it with another mod. Had some cases where it was the solution with another slash format. Just ignore my post before, then. I copied the wrong format again.
@TRDOffroad97 and @chonkie thank you for your answers . But @chonkie as I already have my "modded" version installed, I will just install the "legit" version on disc D and play like this and switch between the two versions.
@itstobi Mainly map mods and interiors. So far I've only made one mlo interior that I've released on the site, working on another one. I've placed many vanilla mlo interiors in my own personal game in custom locations, and also have placed other random stuff all over the map. Still learning more about it. I haven't really messed with converting cars or much else with them besides just adding in the nice ones that others mod.