After ruling out heat, memory including lack of and disk problems such as low space, and errors, I would start looking at assets. Is there anything that you installed and used on your route recently? In order to narrow down the culprit, you need to go through the process of elimination to find the culprit. Prior to doing this, I highly recommend running a database repair and perhaps even consider performing an extended DBR. To do this, press the CTRL-key while selecting Rebuild database. After the repair process, view faulty assets in Content Manager. You will undoubtedly have errors. Select the faulty assets and choose View errors and warnings. Many of these errors will disappear and once done, exit Content Manager and return again to the same view. Most of the faulty content will be reset and if there's anything left you need to delete and replace the faulty assets. There's a possibility that one of these faulty assets is the culprit. Sometimes, though it's not that easy. The issue could be that an asset is corrupted in such a way that it will have no errors but causes crashes. This could be caused by a corrupted texture or mesh and this is where the process of elimination process comes into play.
Go into Content Manager and display only Installed and not built, payware, or DLC.
Select about 100 to 200 assets.
Go to the Content Menu and select Disable.
This will hide the asset from Surveyor.
Load up your route.
Does it crash?
If it doesn't go back to Content Manager and repeat the process again by selecting another 100 to 200 assets to hide (disable).
Load up your route and try again.
Repeat this procedure until nothing crashes.
At this point, you need to find out who the culprit is.
In Content Manager, view hidden assets and select the last few assets.
Test again.
If there's a failure, you then narrow this down by disabling one asset at a time until you find it. Once found, delete the asset and redownload, or install from CDPs or elsewhere if it's third-party asset.
Once done, I highly recommend defragmenting your hard drive if it's a regular drive since the drive will be highly fragmented after this process.
This thing is notorious for just stopping during any part of my work. Then I'll restart the game, try to be careful (huh ??), and