Murphey was well known for his proposals regarding internal improvements, public schools, and constitutional reform. In 1817, Murphey submitted a legislative report recommending that North Carolina create a publicly financed system of education.
In 1819, he drafted a document proposing a program to build roads and canals throughout the state. This proposal was ignored by Murphey's fellow legislators. In 1818, he was elected a superior court judge by the legislature, but gave up the position after two years to concentrate on his worsening financial situation and to research and publish a history of the State of North Carolina. Unsuccessful in securing a seat on the North Carolina Supreme Court, he nevertheless sat on the court in its early years to fill in when any of the three judges on the court had to disqualify themselves because of their previous law practices.
Murphey did not have much luck in accomplishing any of his goals. Many of the results to his plans came after his death. His state history was never written, lacking the funding that it needed. He did however collect papers, the first volume of which are held by Harvard and the second volume by the University of Virginia, that were helpful for later historians. Meanwhile, Murphey's financial problems were getting worse and worse. Being unable to pay his debts, Murphey was even put in jail for twenty days in Greensboro, North Carolina in 1829.