Thanks for the reply!
The current carb is stock to the vehicle, so I don't know it's model number, but I'm sure that I can find out if that would help things.
It is entirely possible that vacuum is part of the problem, here. Unfortunately, I'm so new to working with carbureted systems that I wouldn't really know where to start.
It seems strange to me that the idle is practically perfect in drive and reverse, but revs up really high in park or neutral.
Also, the carb floods quite easily, and absolutely hates to start cold. These are all reasons that it's been suggested to me that I snag a new or rebuilt carb and start anew.
P.S. - amber lamps lulz.