"A carriage and horses, with the attendant servants; in later use sometimes applied to a carriage alone" www.oed.com

The sentimental novel was a popular genre, emerging in 18th century Europe. They aimed to emphasize the value of emotions and "raised the analysis of emotion to a fine art." https://www.britannica.com/art/sentimental-novel

As commonly used today, Timbuctoo is used to refer to "the most distant place imaginable." http://www.oed.com/view/Entry/202099?redirectedFrom=timbuctoo#eid

a city of of West Sussex in South-East England, approximately six miles from the nearest coast

Austen here uses the term to refer to an "enterprise regarded as governed by chance." www.oed.com

an area of land used for raising young plants www.oed.com

the name of the tract of country, formerly wooded, included portions of Sussex, Kent, and Surrey www.oed.com

a small village in the country www.oed.com

A baronet was ranked as the lowest of those with hereditary titles but above all forms of knighthood. http://www.oed.com/view/Entry/15666?rskey=Z33XhD&result=1&isAdvanced=false#eid

Austen is referring to a boarding school attended by young women from wealthy families who, for some reason, were not educated at home by a governess. https://judeknightauthor.com/tag/girls-education-in-regency-england/

Dinner was the primary meal of the day in Regency England and typically took place around mid-day.

Approximately 25,000 families made up the landed gentry in late 18th century England. https://www.historytoday.com/archive/marriage-and-property-jane-austen%E2%80%99s-novels

Austen would be referring to a pocket watch. Wristwatches were not worn, especially by men, until around the turn of the 20th century. https://www.nytimes.com/2013/10/23/fashion/wrist-watches-from-battlefield-to-fashion-accessory.html

a room reserved for the reception of company, and to which the ladies withdraw from the dining-room after dinner; a private room that is attached to public areas of the house http://www.oed.com/view/Entry/57558

According to Merriam Webster a gig is a light 2-wheeled one-horse carriage. See the link below for a picture. http://www.nationaltrustcollections.org.uk/object/272898.1