Good God, there are how many midlist PNR novels published every year? It's a huge genre and still going strong. Ok, against my better sense, I'm jumping back in here.
First, ask what kind of PNR novel you like. You mentioned TV shows like 'The Originals' which is based off a spin-off of a book packager's PNR series (I believe. I never watched 'The Vampire Diaries', and stopped watching 'The Originals' during the second season.) Be aware that screenplays have a different writing style than novels. Good screenplays have just enough efficient direction to 'lead' a skilled director, cast, and crew in their creation. Authors writing novels have to do everything, so there tends to be more set-up and more exposition. I'd seriously recommend you track down some movie or TV novelizations of shows you are familiar with, so you can see the difference. TV and movie plots actually tend to be condensed, whereas novels can include more layers and subplots.
The plot depth you are noticing in 'The Originals' is more reminiscent of soap-opera plots, with constantly-escalating stakes and shifting alliances. This might be another field to look in.
I still can't figure out why you want to pay a ghostwriter and not a writing teacher (so you can learn to wield your own take on the genre), but that's your call, Crossword.
We'll have to agree to disagree about Dan Brown: I find his writing clumsy and boring (but I cut my teeth on secret histories from Tim Powers and Umberto Eco).