*Help with a full-fledged story referencing many of Lloyd Alexanders works*

Hi! Im making a story that borrows many characters and themes from the various books of Lloyd Alexander, especially the Chronicles of Prydain. So far it's about a boy named Erick and a talking book named Stephanus who search for the land for the books long lost memories. The geography is based on Mongolia as opposed to Wales but features important places like Brightford from the Cat Who Wished To Be A Man, Fflewders realm which has grown quite large, important people like Taliesin who becomes a traveling writer in this incarnation, and good ol' Doli who now exists in myth and legend.

tl;dr Basically I was hoping for some ideas of other possible locations from Prydain, Westmark, etc. or characters people would like to see put into this sort of story. Any suggestion would be much appreciated!

P.s I can post more on the story if other friends of Prydain are interested.