As a Regency romance, this is a sad case of young love-at-first-sight for the hero, and with only a few scenes between him and the heroine during the entire book, there's not much to comment on this.
As a mystery, this seems too fortuitous, for there could logically be many reasons why a well-bred young lady would choose to be an upstairs maid aside from her being a runaway bride...so I'll leave it at that.
As a focus on an explorer's club, this is quite fun as it focuses on Lady Lavinia and her two cronies with their ladies observation club - to be honest, the amount of pages devoted to them seems to serve little purpose for the book but to provide additional characters, so the plot is at best muddled, at worst horribly disjointed.
Lady Lavinia is undoubtedly the main character of the book, as much as the blurb fools, and the novel begins and ends with her. The latter half of the book takes a page from Robinson Crusoe with stealing the hero's clothes and fending off an escaped convict in the woods, which is the most fun this book has to offer.