Follow the Ball (Solution)
The title and flavor text hint that "following a bouncing ball", where a ball hits every word, or every letter, is important.
If you take the capital letters from the note, you get the word "siteswap". Googling this word reveals that it's a numerical notation for describing juggling patterns. Each number indicates how many beats later that ball is thrown again.
Each of the five numbers before the cryptic lines of text is a siteswap. Cipher's instructions "one letter per throw" and "follow the first ball" indicate that you should apply the siteswap to the text, using only the letters that the first ball lands on.
423: Evening wash stone.
Eveningwashstone
4234234234234234
e i g h t
5317: Firelit event sent.
fireliteventsent
5317531753175317
f i v e
4013: Time was lost.
401340134013
timewaslost
t w o
453: Find it now, roses will them.
4534534534534534534534
f i r s t
Finditnowroseswillthem
441: Shores sent lively included.
4414414414414414414414414
s e nt e nc e
soonestantepleasonceover
shoressentlivelyincluded
This gives the clue "eight five two first sentence", or, apply the siteswap 852 to the first sentence of Cipher's letter.
Over the ash town, I reach a stitch in shadow.
OvertheashtownIreachastitchinshadow
85285285285285285285285285285285285
o s t r i c h
This gives the answer, OSTRICH.