Ready to have a place to rest (4)
I believe the answer is:
seat
'to rest' is the definition.
(thesaurus)
'ready to have a' is the wordplay.
'ready' becomes 'set' (set can mean ready or prepared).
'to have' means one lot of letters goes inside another.
'set' placed around 'a' is 'SEAT'.
'place' is the link.
(Other definitions for seat that I've seen before include "Take one and sit" , "Place to sit" , "Horizontal part of a chair" , "Somewhere to sit" , "Chair, bench, or stool, say" .)