This is the sort of simple, straightforward material that characterizes solid TSoY scenario preparation: some history, some crunch, social principles upon which to build people, a player character concept. Just add a mix of characters and go.
In the heart of the Valley lies Casnic, now an abandoned nest of ratkin. The beasts are addicted to the farro, which they eat or burn in water pipes scavenged from the ruins.
An elf lives in Casnic, one going by the name of Slusch Bash. She wields Three-Corner magic and alchemical powers akin to those of the Assartist, but none know for what purpose. Other elves visit her out of curiosity, but none stay long.
It is possible to bring animals to Sireap, it’s just that the farro is so unexpected. Enter after or during rains, and you might have a week. Come in winter and you could have a month. But sooner or later you’ll find the horses dead and the dogs at your throat, or nowhere to be seen.