So here is the system I use:
Almost all problems related to a map that CTDs before it loads is related to the XML files in your CustomAssets\XML directory tree. Of course you also need access to the .nif, .kfm, .tga, etc. files that the XML references.
I have all kinds of maps "installed" in my CustomAssets\XML\_SCENARIOS_ directory, and they all load fine as long as I stick to the following file structure:
CustomAssets directory
<necessary .FPK files>
- XML (directory contains global xml files)
- RRT_Trains.xml (contains all trains for all maps)
RRT_TrainCars.xml (contains all cars for all maps)
RRT_Goods.xml (contains all goods for all maps)
...
- _SCENARIOS_ directory
- CustomMap1 (directory contains map-specific xml files only)
- map_CustomMap1.tga
map_CustomMap1_thumbnail.dds
RRT_Goods_CustomMap1.xml
RRT_Trains_CustomMap1.xml
RRT_TrainCars_CustomMap1.xml
...
- map_CustomMap2.tga
map_CustomMap2_thumbnail.dds
RRT_Goods_CustomMap2.xml
RRT_Trains_CustomMap2.xml
RRT_TrainCars_CustomMap2.xml
...
- map_CustomMap1.tga
- CustomMap1 (directory contains map-specific xml files only)
- RRT_Trains.xml (contains all trains for all maps)
Likewise, the RRT_Goods.xml must contain all the goods from the base game + RRT_Goods_CustomMap1.xml + RRT_Goods_CustomMap2.xml + ....
So when you download a map that has new trains or train cars, or goods that are not in the base game, these new trains, train cars, and goods must be added to your global XML files, or the map will not load.
Another rule to this is that no global files can appear in the individual scenario directories. So RRT_Trains.xml should only be in your XML directory, and not found in any of the individual scenario directories. So I removed the RRT_Goods.xml and RRT_Trains.xml files from the Santa directory, but copied the new goods (Rocking Horses, Toy Soldiers, Teddy Bears, etc.) to my global RRT_Goods.xml file, and the Holiday train to my global RRT_Trains.xml file before removing these files from Santa. Not doing this may cause another map to not load.
So now I am able to load all maps just fine.
I have this structure set up for you to download for the ChicagoToTheRockies and SuperBowlExpress maps since I ran into this when creating these maps. These maps work fine with Santa and Scrooge because the global XML files contain all the elements from all four maps (and all the base maps of course).
This update is on page 2 of the ChicagoToTheRockies topic if you want to download and take a look.
Keep in mind that settings in the global XML files are what is used if nothing is specified in the map-specific XML files. Therefore, setting the prices of bridges and tunnels in the global XML file will affect all maps that do not set their own prices. The solution to this is to leave the global settings alone, but modify the prices in the map-specific XML files.
Please let me know if you have problems with this solution with a specific map or maps and I can look into these maps.
Also let me know if implementing this solution has or has not solved your problems, and which maps you have in your _SCENARIOS_ directory.
Hopefully we can all be playing all kinds of maps without frustrating loading troubles.
choobacca