Metes and Bounds

I made a trip into Winterset yesterday to visit the Madison County Courthouse and discuss metes and bounds with the Assessor's Office. It seems during a recent dispute about a small piece of property that lies along my south pasture boundary, the Assessor's Office discovered that the legal description of my property contains pieces of land that are also included in the legal description of my neighbor's property...and vice-versa. If you look at the map to the left, my land is outlined in red; the Cunningham's land boundary is the dotted blue line. The orange hash marks indicate the two pieces that are in both legal descriptions. It seems that at some point in the  distant past, whoever did the legal description for Cunninghams used the creek (dotted line) as the boundary; whoever did my property shot a straight line north to south. Neither description appears to have been officially surveyed. It looks like we're talking a little less than 2 acres in common. Since I have no access (without going thru my neighbor's field) to the piece on the other side of the creek, it seems reasonable to me that should be his; the small piece on my side of the creek should be mine. I'm more than happy to use the creek as the official boundary. Now....how do we make that happen without spending a boat-load of money on attornies and surveyors? Ah, good question!