UPDATED (13th April): In the light of this forum post, I did some further experimentation with kinc_crafting (which I eventually found) and can now recommend the following structure for basic crafting. i.e. When not requiring TRADE ITEMS.
First of all locate kinc_crafting.NSS in the SoZ expansion campaign folder. Open this with a basic text editor (like notepad) and copy the script into the toolset as a new script and name it the same. i.e. kinc_crafting (without the NSS suffix). The only other file you require (to make this script compile correctly) is kinc_trade_constants, which can be located in the same way as described above for the previous script. Again, copy and paste the script into your own module, keeping the same name.
Open your kinc_crafting script and add the include line for the kinc_trade_constants file. i.e. Add the line #include "kinc_trade_constants" just below the other include files mentioned in the kinc_crafting script. Lastly, add the #include "kinc_crafting" include line inside your own On Module Activate script, which will also contain the modified script as mentioned in this blog post.
Using the kinc_crafting include file instead of the kinc_trade bypasses the check for TRADE GOODS. However, you may still like to replace these goods (as described in the original post below) so that the player still has to acquire ingredients similar to the original TRADE GOODS. If you do, simply carry out the instructions below, but now without the need to delete the COST_GOODS and COST_RARERES columns first.
I thought I would share a couple more things with fellow builders with respect to crafting using SoZ code. First of all, if you have tried opening the nx2_crafting.2da file, you will have probably found that it has errors that prevent it from opening in some 2da editing programs. For those interested, here is a FIXED FILE that you can download. This file is required for those who may wish to edit it to either add or change those recipes that are available in the game.
In particular, you may wish to remove any references to TRADE ITEMS required to craft items. These items appear under the COST_GOODS and COST_RARERES columns and refer to TIMBERS and INGOTS. For basic crafting, you will NOT want these columns to contain references to any items, but want to add items (replacing these trade goods) with specific ingredients to the COST_ITEMS column instead.
E.g. In rows 97 and 98, I have removed the GOOD_TIMBER reference from the COST_GOODS column and added specific tags representing the planks instead. (See screenshot.) Now, when the code checks for the items required to make the different types of poisonous arrows, it will not fail when checking for TRADE ITEMS (which we don't want in a basic crafting system), because they are no longer listed, but will require specific planks of wood instead. In our example, I have made the requirements a Zalantar Plank for mild poisonous arrows and a Shedderan Plank for poisonous arrows.
Continue to remove unwanted TRADE ITEMS from their respective columns and add appropriate planks of wood or ingots as required. In this way, you can keep all the recipes that can be found and make use of basic crafting items rather than have to rely on the TRADE system.
Just for your information, I have also discovered a number of errors with respect to items required for the crafting (in the 2da file), descriptions of such (in the recipe description), and even in the resulting item itself (item object). As an example, these two lines that supposedly make two different types of arrows, actually make an arrow with the same qualities! Of course, it is easy enough to add or alter the properties on the arrows and make a new campaign item (that will be created instead), which is what I have done. Just remember to ensure you have the name, resref and/or tag set exactly as the 2da file requires or the item will not be made.