The best way to avoid crashes when playing singleplayer is to launch the game in -debug_mode. You can google "imperator rome debug_mode" on how to do it. Documents\Paradox Interactive\Imperator\crashes\ are where the crash logs are. The bottom most is usually the most recent. then logs-error.txt. If you run into a locators crash, you're screwed. All other crashes are fairly easy to fix. If your game crashes without a log, it should be a memory issue where your game isn't getting enough memory or CPU power to run it. In that case, close tabs or applications. I've tried making the mod fairly lightweight, so it shouldn't affect your performance by too much, since there isn't much in it.
The mod should be installed to Documents\Paradox Interactive\Imperator\mod
Country files are in AncientEstonia\setup\countries and \germania.
This is useful if you get color errors for a country.
Province files are in AncientEstonia\setup\provinces and 00_baltic_sea_region.txt
This is useful if you get any province errors.
Name files are in localization\english
This is useful if a province or country is named something like PROV8067 or XHA.
Object locator files are in AncientEstonia\gfx\map\map_object_data (to change locators, run with -mapeditor)
Alternatively you can place locators like I did, which is running the game in debug_mode and checking positions manually. The required locators are city, combat, fort, great_work, port, unit_stack and vfx. I have already placed them, but if you have errors, you know where to find them.