If you want to shoot on your own property aside from county regulations, you then have to look at city regulations. If you are anywhere inside King County i can Guarantee you that you will never be allowed to shoot on your own property. I am a member of The Interlake Sportsman's Association our members are regularly involved in trying to get more gun ranges open and keep the ones in existence open as well. Each day it is harder to do, mostly because annexation laws have been recently turned from a vote of those people on county land being annexed to an "asked and answered" policy that allows counties to annex properties they no longer want to take care of to be automatically annexed into any city that wants them.
If you let me know which county you are headed to i will see what info i can dig up.