Castle laws pertain to "Your home is your castle", and maybe business. I'm not aware of any that touch on property, they just make it clear you have no duty to retreat from your home (ADDED: true in 46 states according to Wikipedia), and the better ones allow you assume a home invader is a lethal threat, as you can reasonably assume about anyone invading an occupied dwelling. Otherwise proving that could be lethal to you, e.g. challenging the intruder gets a bullet in reply.
Note as usual all this is subject to judicial nullification, in my home state of Missouri as of 2010 the latter part of our crystal clear Castle Doctrine has been nullified through middle level appeals court required jury instructions. Our higher level judicial appointments are not surprisingly done according to the Missouri Plan (http://en.wikipedia.org/wiki/Missouri_Plan), so the usual suspects control the process, not the people through their elected representatives.
Note as usual all this is subject to judicial nullification, in my home state of Missouri as of 2010 the latter part of our crystal clear Castle Doctrine has been nullified through middle level appeals court required jury instructions. Our higher level judicial appointments are not surprisingly done according to the Missouri Plan (http://en.wikipedia.org/wiki/Missouri_Plan), so the usual suspects control the process, not the people through their elected representatives.