Looking up details about them I was surprised at their publication dates:
The Enchanted Wood (1939)
The Magic Faraway Tree (1943)
The Folk of the Faraway Tree (1946)
Up the Faraway Tree (1951)

All 4 stories focus on an enchanted wood with one gigantic magical tree discovered by three adventurous siblings (Jo, Bessie and Fanny) allowed to explore at random in days gone by when children’s freedom was unrestrained.
At the top of the Faraway Tree is a ladder which accesses a magic land - a different place every time they visit - but not always entirely pleasant - and there is always the tension of making sure they get down ther ladder before the land moves on. Great excitment and along the way they meet the folk of the Faraway Tree including Moonface, Silky the fairy, Saucepan Man, Dame Washalot, Mr Watzisname and the Angry Pixie. Great characterisation, as I remember.
Long before I had children I remember reading this book to my younger sister and stimulating her imagination to such an extent that she and the boy next door when off on their own adventure looking for the Faraway Tree in our pedal car. (Eventually found some hours later by frantic parents.)
Haven’t read it recently but will dig it out at the appropriate time for my grandson - and hope the language doesn’t disappoint.

I’d love to hear more on any ideas for age appropriate chapter books when you get the chance.