Yep, unfortunately there's very few places anywhere around Sydney to do this type of event - we tried to book around September last year for this year's events, and could only get long weekends, that's how hard it is to get dates (will be looking into booking next year's stuff pretty soon then!).
(incoming explanation/rant)
It sucks, but unfortunately we can only do the best with what we've got. We try and run these events at absolute break even to keep the costs down and attendance high. There was recently an increase in fees for entrants, a small fee for passengers and also costs for food/drink as we can supply; this is because our cost of hiring the venue has gone up by about 30-40% in the last 2 years. We tried to absorb the cost last year by having 40 entrants per day, but it was giving people the shits because people weren't getting enough runs, so we dropped it down to 35 and then 30 (from memory) so that everyone gets heaps of runs, has heaps of fun. It's just unfortunate that we need to charge a little more to break even instead of running at a loss. We'd love to do it, but it's just unsustainable, especially that everyone involved in running the days give their time voluntarily.