Yes, I have seen that as well. That is where I assumed the railroad went from Camden to the Mississippi along the Chicot Trace. From you info and Brown's Diary, we may infer that it was headed to Pine Bluff on the Arkansas River first. Since the name didn't include the Arkansas River, I assumed it would have taken a more Southern Route. Then again, inferences can be misleading and the route may have turned South before it got to the Arkansas River. If you find out more, please let me know.

Can you share the letter you have? Is it published or a private holding?