Chapter 4.
The story of Eglantine chasing little Pippin and the cat around the farmyard can be found in The Mathom.

Chapters 4 and 8.
The story of Pippin having a splashing contest with Folco and falling in the well can be found in A Healer's Tale, chapters 11 and 13.

(Just in case you wanted to know...)

Epilogue turned sequel
A sequel to this story is in the works (Family Matters), and on the schedule to be published in full once some of the current WIPs are published to the end.