Post Ranch is a Virtuoso property if I remember correctly, so it would be a good idea to book it through a Virtuoso agent. Perhaps they could work some magic with the room rate. Other than that, the only way to get a deal is to call and ask. Tell them what you're looking for and ask if they can offer any discount.

If you haven't stayed in Big Sur before, they have some of the same fog issues we have in the Bay Area, though I don't go there regularly enough to be able to predict it like I can here. In other words, you could spend $1000+ a night and basically not have a view of anything.

The last time I went to Big Sur we spent a night at the Highlands Inn on the way down and hiked around Point Lobos, then stayed at GlenOaks, which I highly recommend (though it's a very different experience than Post Ranch or Ventana). Make absolutely sure to eat at least one meal at the Big Sur Bakery, and if you go to Deetjin's for dinner I can't stress enough how critical it is to bring your own wine. They have totally piss-poor wine menu.