Hints: Galaxy Trucker

Getting started:
The text messages and the Galactic Directory form a logic puzzle that lets you deduce the positions of all 100 cards (in a 10x10 grid, as mentioned in the first message), as well as the uncle’s location on every day. The uncle moves exactly one square north, east, south, or west on each day.
The very last message says “Well, now I can say I've been nearly everywhere in the galaxy!” That hints at where to look next.