Personally I would never trust a builder to disclose anything about the surrounding area. If the surrounding land has not been built upon you should research it to find out what might be popping up down the line. Calavera hills is one such example. Essentially all of the surrounding land has plans in the works; one development is called Robertson Ranch but there are some smaller developments as well. The best place to find out about future projects is to go to the city of carlsbad website and look under construction updates. It is possible to find out some details about planned housing projects, density of housing, etc. It probably doesn’t give all the information you need but it is surely more than a builder would be willing to admit.