Joseph only mentions Adelaide briefly -- touring Richmond with her and while in Norfolk staying wtih A.L Hill (believe that to be Adelaide's uncle Andrew Leighton's Hill), he mentions that Adelaide may not have enjoyed Mrs A L Hill's strong Southerner "freely spoken opinions". When Joseph reaches Boston, Adelaide heades for Dover and he describes spending time with other relatives to include her sister Maggie (Margaret Leiighton Hill, b. 1851)
Adelaide was born about 1847 to Abigail Burnham Shackford (Oct 28, 1812) and Dr Levi Gerrish Hill (Jul 7, 1812), a prominent physician. She was the third child of four girls with sisters Clara Ann, Abby Augusta, and Margaret Leighton. I think Adelaine was actually named Mary Adelaine Hill at her birth because this is how the third child in the family in the 1850 and 1860 census is listed but in the 1870 census she listed as Adelaide S Hill. Adelaide may have been a teacher in Concord as there is a Miss Adelaine S Hill listed there in 1880-1881. In 1886 at the age of 40 she married Rev James Munro Buckley, a methodist clergyman and moved with him to Morristown, Morris, New Jersey where she died April 23, 1910.
Adelaide doesn't have any descendents so why write about her? Well it's interesting to think about a 20 year old young lady travelling from New Hampshire to Norfolk, Virginina and back in 1868. While it's common today for young women to travel alone or with family or friends, in those days in Joseph's diary, traveling from Virginia to New Hampshire was considered "going abroad in the world".
References: Johnston, Joseph S, editor, "The Diary of Joseph Wesley Shackford" p. xiv and 1-20
1850, 1860, 1870, 1880 censuses for Dover, Strafford, New Hampshire
New Hampshire Marriage Records Index, 1637-1947 (ancestry.com)
New Hampshire Death and Burial Index, 1654-1949 (ancestry.com)