Walden
by Henry David Thoreau
One of the progenitors of HermitLit, Thoreau's account of living self-reliantly at the side of a pond includes pages listing his supplies and expenses.
You may not actually read this book, but its utility will become apparent should you decide to never return home.
The Sheltering Sky
by Paul Bowles
When a Manhattan couple heads to Northern Africa to repair their relationship, the wife has an affair with a mutual friend. The tragic conclusion--in which the husband falls seriously ill and his wife goes native with a caravan of nomads--is either depressing or a relief, depending on your own marital status.
The Water In Between
by Kevin Patterson
The British Columbian's sailing memoir tells of a voyage into isolation prompted by the most classic motive of all time: love gone sour. After a nasty dumping, Patterson heads off into the Pacific, at one point going 31 days alone at sea. You should be fine for a week.