]If the Lucases and Lizzy arrived in London "by noon" how could "the morning [pass away] in bustle and shopping"? Wouldn't the morning already be spent in traveling

The Georgian/Regency morning did not agree with our present day definition.

The "morning " was usually delineated as the time between breakfast(taken around 10am ,or perhaps even later in fashionable town circles), and dinner,which for example was served fashionably late at the Bingley hosuehold at 6.30pm.

During the 18th century the hour for dinner became later and later .For example Samuel Pepys took dinner at midday or just after,but gradually , in fashionable society ,it was eaten at a later and later time;the Prince Regent , when he invited himself to dinner at Uppark in Sussex in 1795 stated that he expected it to be served between five and six o'clock.)

So that period of eight and a half hours was called the morning.

Which leaves Lizzie,Jane and the Gardiners lots of time fffor shopping ;-)

Shops in London at this time usually kept quite long opening hours.As Alison Adburgham in the Chapter "Shopping during the Napoleonic Wars "from her execllent book"Shops and Shopping relates;