So, what I want to do seems like it should be extraordinarily simple. I need to grab the name (not load it) of the next scene, as listed in the build settings.
I thought I had a simple solution by doing something like this:
int currentIndex = SceneManager.GetActiveScene().buildIndex;
string nextSceneName = SceneManager.GetSceneAt(currentIndex + 1).name
Yes unfortunately you are right, but...You're in luck!
I created a plugin/asset for that after reading your question, it's three small scripts and it should 'just work' and using it is literally just one line of code:
var buildSceneRecords = BuildScenes.Records;
The records contain the name, path and index for the scenes in the editor build settings.
You can get it here: https://github.com/sindrijo/unity3d-runtime-buildscenes