If it IS racing season, ignore the Hilton Del Mar...it is next to the entrance to the track so will be highly booked then. We got "off" racing season during last July and booked two rooms through Hotwire at $60/room.
Here's my secret for booking hotels on Hotwire...first ask it to quote you a package w/air and hotel and you will get choices of which hotels for your package (names, info, stars, location)...note which hotels you like and their location and star amount, then go back and do your search for hotel only (won't tell you names, just location and stars)...you will know the exact hotel from looking at the packages before and can book w/confidence. We've ALWAYS gotten the exact hotel we thought it would end up being using this method.