Although I am blessed to have a first edition of Cartwright's "Autobiography" and have read serious portions of it, I cannot say that I have read through every word. However, from my reading in the "Autobiography" and coming across him in other books (as well as a little research for this answer), I will make some comments.
Peter Cartwright (1785-1872) moved with his family to Kentucky in 1802. There, as a young Methodist preacher, he got to experience the Second Great Awakening first hand. He was the frontier-type preacher who knew how to rough and tumble. His escapades makes one think of a religious Davy Crockett or Daniel Boone and his story is worth hearing and telling. I believe it was Cartwright who was asked to dance at a tavern and through shear audacity turned the dance into a prayer meeting and preaching service.
His doctrines and prejudices were that of old-time Methodists. He believed in baptizing babies and spoke strongly against the Baptists. He would also have believed in the possibility of losing one's salvation. In later years, he moved to Illinois and worked in churches there. He also ran for state legislature three times, losing only once. In 1832 and in 1846, his opponent was Abraham Lincoln. Cartwright won the first time and lost the last time he ran against Lincoln.
I believe that Cartwright's story is a good one and one that needs to be remembered. His writing is a bit braggadocios but he lived big and perhaps he must tell his story big. For a Baptist like myself, I cannot look to him for too much of an example. He certainly believed and supported false doctrine (as far as I am concerned). He should not be turned loose on new believers who have not settled their own doctrines. Many people who sell his "Autobiography" and tell his stories do not know his background. He could not have been my friend had we lived in the same time, but I can still rejoice in his victories for Christ.