I guess I've been spoiled by a rural record keeping system. One has to take particular care to identify improved property around here. Jethro's daddy gives him an acre to put a wobbly box on, but Jethro never records the deed. Daddy wants to refi. Jim's gotta find Jethro and get his deed to find out what Daddy still owns. Then you find out about the easement Daddy sold to the crop duster outfit some decades back to land and reload duster planes. Try to find THAT one in the courthouse--if they recorded it at all.
Once a particular tract is identified, though, I find a qualitative analysis based on geometry, size, topography, appeal, and access to do the job rather nicely for most unzoned vacant land. Feasible uses are constrained by size, usually. Sometime by topography. We don't do timber, crops, minerals, livestock, or machinery. For zoned land, the fact that legally permissible uses are limited simplifies the HBU problem for residential tracts. Commercial/industrial zoning is another animal altogether.
For my part, I really don't think vacant land is any more difficult than a #!@)*&%(* wobbly box that's been added onto three times, foreclosed on, and rented to the owner's son-in-law -- and they want a 90-day quick-sale value in a 360-day market. Those Ray Miller assignments make you tough, if they don't kill you.
