A "coaching town" is a village that has grown up
around the intermediate stops or "posts" of
a mail coach route.
It is the genesis of the word we use "post"
"Australia Post" "postage"
The first mail coach route was london to Bristol
and Bath, to get the news from the colonies, from
ships and packets arriving from overseas destinations
that pulled into Plymouth
(That's how Stanley Gibbons got his first
Cape of Good Hope stamps)
His (father's) shop was in Plymouth.
The "posts" were generally about 12 miles apart,
people could get refreshed (usually weak beer, because
often water was too foul) water the horses, and take
on freight.
A coach:

The "horse posts" London to Hull, going North in 1677
Later on, Ilford would probably be on this route
