purchasing a home in CA. part of the structure (an addition) is over the property line on government land (national forest). the house was built in the 60's, im not sure about the addition, but it looks old as well. this came to my attention when the realtor showed me plans a previous owner had for a garage that would go over the property line and showing part of the existing structure already over. i would like to add this garage if i purchase the property. not sure how adverse possession applies to government land, existing, and proposed structures. long story short, should i buy this house?