What insights does this book give into the potential opportunities and challenges that men had for social advancement in early 19th century New England?

Let's face it, the wave of men immigrating to the New World at the beginning of the 19th Century weren't crossing the ocean with the intent of settling for a life they could have lived at home. Those men traveled here to better their lives and take advantage of opportunities they'd never have found in their homelands. Education opened doors, craftsmen were in demand, businesses were opened, and advantageous marriages were made. 

As far as moving up the social ladder, Ichabod (or any educated man) would have acquired the knowledge and manners to advance in society, but it would have been a long hard journey to acceptance. The opportunity to make your fortune didn't mean you could mingle with the "old" money...... the landed gentry...... those who came to America already wealthy and sought to increase their wealth here. Snobbery still existed, and it still does, even today.