The nice thing about the first Hopkins book is that it has a happy ending.
Hopkins seems to have been in Vegas as the preparations for the TTWII movie were in hand and in the very final chapter he mentions Elvis' September 1970 tour dates. So it ends with Elvis at the top of his game. For this reason I've never been able to bring myself to read the follow-up book.
Jerry Hopkins 'Elvis' is useful as a primary source in a similar way to Hunter Davies' 'Beatles' biography published in 1968 when the group were still together.