I was tooling around the Intrnet tonight and found out that the Wilson Library has a great eLibrary that has many of his letters (and his family's) available both as a transcript and an image of the original! For instance, here is part of a letter from Ellen Wilson to Woodrow Wilson in 1904:
My own darling,
I am writing,—with an impossible pen,—in a window looking out upon the bay of Naples,—Vesuvius, and Naples itself across the water,—a wonderful prospect indeed, though robbed of a part of its glory by an overcast sky. We left Amalfi at 8.30 and had a wonderful four hour drive through the wildest and most picturesque scenery. The air was so deliciously fresh & cool that it partly atoned for the absence of yesterday’s intense colour. Yesterday was the most glorious day we have had. It was a perfect riot of colour,—a debauch of beauty from early morning until night. We went to bed feeling positively drunken. But to return for a moment to the beginning. We left Naples,—on a train that went about a mile an hour—reached Pompei at lunch time & spent the afternoon in the ruins. It was intensely interesting even more so than I expected;—very hard walking however for several hours; we reached La Cava at dinner time rather used up. After a very comfortable dinner & bed we started bright & early for Paestum. It threatened rain but held up for a time and we had a beautiful little railway journey & then a pleasant walk to the temples,—which are all my fancy painted;—no picture can give the impression of their majesty and nobility. While we were still at the temples the rain began in good earnest: but we were prepared for it and got no harm. Indeed the dark skies rather suited the melancholy beauty of the place.—
What I found was interesting was that she signed herself as "Eileen!"