Constantly though casually following a little chap (7)

I believe the answer is:
solidly
'constantly' is the definition.
Both the definition and answer are adverbs. Maybe you can see an association between them that I don't see?
'casually following a little chap' is the wordplay.
'casually' becomes 'idly' (I've seen this in another clue).
'following' is a charade indicator (letters next to each other).
'a little chap' becomes 'sol' (I am not sure about the 'little' bit.).
'idly' after 'sol' is 'SOLIDLY'.
'though' acts as a link.
Can you help me to learn more?
(Other definitions for solidly that I've seen before include "Working in a financially sound way" , "Reliably, firmly" , "with substance" .)
