As Hazelnut mentioned, you'll find the quests scripts in the
StreamingAssets/Quests folder (you can ignore .meta files on git). In your builds, this path is in DaggerfallUnity_Data\StreamingAssets (right next to the DaggerfallUnity.exe). The quest scripts are compiled at runtime so you can make changes and test them live in the game.
You'll only need a simple text editor to edit the quest files now, but you'll still have problems with the limited UTF8 character set Daggerfall uses. The FNT files are also included with builds now, you'll find them in the
Assets/Resources folder. So any changes you make to the character set will also be ignored unless you replace the FNT files and create a new build as well. I need to have FNT files available to bootstrap the UI before user can even set their Daggerfall path.
There are also a bunch of strings that are baked into FALL.EXE that have been migrated to
HardStrings.cs. Daggerfall unfortunately keeps text all over the place without a very disciplined approach, and Daggerfall Unity is forced into much the same trap due to using the same classic data (with exceptions of FNT files, quest scripts, hard strings).
It might be beneficial to setup a git fork of Daggerfall Unity project then others in the Spanish-speaking community can collaborate on editing the quest and source files while keeping them up to date with any changes to source.
I would clearly like a better approach to translations in Daggerfall Unity. This was a goal early on before I learned the full extent of how difficult a process this would be. Daggerfall itself makes no concession towards localisation, which makes it very difficult to build this layer in without sacrificing some of my other goals. It's something we as a community should be able to improve later in the lifecycle but right now I'm mainly focused on gameplay features.
