I enjoyed the text adventure in the Jungle Adventure pack and I want to use that as a basis to make a new quest in The Sims 4. I'm looking to create something similar to what's in The Sims Medieval.


I'd appreciate any information on custom text adventure quest.

The best resources would be to look into tuning modding in general, which is what the vast majority of things in the game are made up of.

Lot51's TDESC browser: https://tdesc.lot51.cc/ - The most valuable tool, use this to look up what tuning files are used for the rabbithole popups already ingame.
Zero's modding tutorial series: https://www.patreon.com/posts/new-tutorial-for-82731352

Once you are familiar with the most important tools and steps, you can apply that knowledge to just about any project you want.
Find the most similar EA tuning, use it as a framework to make your own. If you run into specific issues along the way, it might be worth asking at the Sims 4 Studio forum- it's a little more active than here.
Best of luck.