Isaiah 8:6 (King James Bible) forasmuch as this people refuseth the waters of Shiloah that go softly and rejoice in Rezin and Remaliah’s son
We do not have the original manuscript for 2 Nephi 18:6. In the printer’s manuscript, Oliver Cowdery first wrote “go softly along”, probably because he expected some adverbial complement to “waters ... go softly”. His crossout has the same level of ink flow as the surrounding writing, so his correction seems to be an immediate one—and in accord with the text of the King James Bible.
Summary: Maintain the corrected reading in 𝓟—that is, without the along that Oliver Cowdery initially wrote after “go softly”.