Is there anyone who analyzes where the MONEY in the primary season is being spent? TV? local parties? local consultants? Who is benefiting from an extended primary?Great question, but I only have a partial answer. Generally, official campaign committees must disclose what they are spending, in some detail...but whether reporters dive into those disclosure statements, and how complete they are, are open questions. PACs (and Super PACs) have to disclose their spending, too, but with the same caveats.
On the plus side: you probably want to read what the Wesleyan Media Project, headed by Erica Fowler, Michael Franz, and Travis Ridout, have to offer. They "track and analyze all broadcast advertisements aired by or on behalf of federal and state election candidates in every media market in the country." So that's a big chunk of your story, right there. Open Secrets has some spending information (see e.g. Mitt Romney). but I haven't poked around there enough to know whether it gets to some of the things raised in the question. You can also go straight to the FEC for disclosure statements, if you want the raw data. Again, whether anyone is turning all this into useful-sized findings is a more difficult question. There's always some disclosure-based reporting, but probably not as much as some would like.