I seem to remember seeing chords numbered in that "Nashville" manner as being printed as roman numerals rather than regular arabic numbers ~ for example, I IV and V7 for the standard three-chord songs, etc.

I understand tab quite well, and can even write it when so motivated and when I have enough time on my hands. But I don't clearly understrand what might be meant by "E in the D position": does that mean capoing up two frets and playing key-of-D "shapes," resulting in key-of-E pitch? Or something else?

There are quite a few different lyrics to this great old song. I myself had never encountered the first verse referred to in the above links: our shanty group sings the first two lines as "Farewell to Prince's Landing Stage / River Mersey, fare thee well."

And then there's Bob Dylan's alternative lyrics, entitled either "Farewell" or "Restless Farewell." Both are revisions of traditional songs, and both come from Dylan's early days before be began to record. One is a reworking of this song, the other of "Parting Glass"; I can't remember which title goes with which song.

I'm partial to Bob's lyrics on the verses, but on the chorus, I much prefer the traditional words, because "It's not the leaving of Liverpool that's grieving me" scans better, and fits the melody much better, than "it's not the le-e-e-aving that's a-grieving me."

The Dylan version is in the DT; it appears under a title something like "New Leaving of Liverpool" rather than Bob's title, but the commentary clearly notes the source.