You know what , as many other modeler unwrapping task make me mad sometimes but
fortunately and because the work of smart people you can get tools around there how will make your life easier.
If you use XSI ( like me ) or maya even 3ds max go see here.
This is the page for RoadKill plugin for XSI , from there you can go grab this unwrapper
for maya , max or use as stand alone version.
This is pretty powerfull and simple to use , integrate well in XSI worflow, and best of all It's FREE !!
So worth trying it