Ironically we are selling our home and 10 acres also, with a view to die for and heading for Montana.
I am trying to sell 37 acres outside of Enumclaw and head to Montana as the restrictions and permit fees are just plain insane. Good ol fat ass Ron Sims and his dictoreal rulings of King County.
It depends on what zoning code the county has designated. Much of that area is zoned RA5 (rural agricultural one home per 5 acres), ra10,(one home per 10 acres) etc. Several of the larger pieces (maybe the 26 acres you are interested) have been zoned so that only one residence can be built. Another issue is how many wetlands are on the property. Very strict building restrictions and set backs.
Send me the tax parcel number or location and I will check zoning to see what it calls for. King County is virtually impossible to get zoning changed. Most areas are changed after they are annexed by a city.
The issue of a mother in law is a different story. Really depends on what and how you build and is specific to the zoning of each tax parcel.
Call me at 206-696-2329 or send an email with the parcel number or exact address or location to Gary@GaryMcNinch.com and I'll be glad to follow up with you.
Good question, good to do your due diligence. Cold Bay ???