How endless a build-up do you want, or need? Racing adherents will have followed the horses throughout the year - they know where they're trained, who's going to ride them, and probably the most ardent will have every nuance of ratings, going preferences and other arcana on their Excel spreadsheets. If the Festival is going to essentially receive nonstop days of free advertising (because that's what it amounts to), then concentrate on the main races' favourites, visit them for a look round the yards and a quick, insightful chat with their trainers, meet their adoring grooms, and have a very brief chat with their jockeys. End of - woefully irrelevant reminiscing by has-beens over dinners, early morning rambles (in all senses) round the gallops, twitting on about how good this or that looks, etc., do absolutely nothing to entrance newbies, and just bore the knickers off the knowledgeable.
It's the raceday itself which sells - or doesn't sell - to the 'general public'. I doubt that Cheltenham needs to sell itself, any more than Aintree, Royal Ascot, or Glorious Goodwood. People who don't usually go racing go to these events to be part of a huge, sociable crowd - something to tell their friends/impress the neighbours, whatever, or just to try something new. Plus, there's enormous hospitality uptake at these events - local and not-so-local companies will have been bombarded by the courses' Sales & Marketing people with e-mails, letters, and cold calling for months, as well as getting slots on local radio to keep up the commercial pressure. There's no need to keep wasting time on fawning 'interviews' which reveal absolutely nothing.