For The Legend of Heroes: Trails from Zero players, this guide will show you a mod that ports over the Vita-exclusive quests to the PC version.
Info
There are a number of quests that are only present on the PS Vita version (Evolution). I decided to do something[github.com] about that. (The number is five by the way.)
Download the latest release[github.com] (can be extracted with for example 7zip) and merge the data/ directory into the game files. The game directory is normally at C:\Program Files (x86)\Steam\steamapps\common\The Legend of Heroes Trails from Zero, or you can find it by right-clicking the game and choosing Manage » Browse local files.
The quests
I won’t give any walkthrough for the quests themselves; find a different guide for that.
Ultimate Bread Showdown!: Chapter 2, first day, after returning from Armorica Village. The aftermath happens in chapter 3, second day.
Search for the Oversleeping Doctor: Chapter 2, second day.
Search for a Certain Person: Chapter 3, fifth day.
Clerk’s Customer Service Guidance: Start of chapter 4.
Guest Lecturer for Sunday School (Continued): Start of chapter 4. Requires having done Guest Lecturer for Sunday School, as one might surmise from the name.