I just saw your post and jumped out of my chair! My family has two very large paintings by a R.P. Thrall dated 1874. The first painting is of my GGGrandfather, John Stum and the second is of the Stum farm house and property outside of Maytown, Pa. I have for years tried to find out who R.P. Thrall was. I hope this is our man. I would appreciate any info you would like to share. I can send you a picture of both of the paintings. Thank you, Gretchen and James