The first letter describes the spiritual turmoil that Dudley is experiencing as he his torn between leaving to California and the thoughts of going back to his wife and children.

The second letter tells us how, due to a strange change of fate; Dudley manages to obtain passage on the vessel Brother Jonathan. The vessel sails in early December 1851 and Dudley apparently arrives in Panama where he contracts Yellow Fever and dies some days after.

Mary Ann later re-married Mr. William Fetzer.

There is a legend that Dudley managed to survive and established himself in Mexico where he married and had many descendents.

An excerpt of the original handwritten letters is shown below: it contains the vessels name and destination, it may help in tracing exactly what happened on December 1851...
We do know that the Brother Jonathan sank off the coast of California in 1865, with a treasure worth over 50 million dollars.
Apparently this ship sailed to the Chagres River in Panama where people would cross the istmus. In such a journey Dudley got bitten by mosquitos and died of Yellow Fever