To smooth the rear end I removed the bumpers, bumpercaps, bumper shocks, along with all of the side marker lights. Then cut metal patch panels to cover all of the holes. Once those were welded in place the whole panel was given a good grinding. As you can see here.
http://zdriver.com/rides/detailride.php?cat=1&relIdx=16&vehId=42
Then skim coated the panel with bondo and then polyester spot putty. I had an expert body guy sand it down for the proper look. I have other "in progress" pictures if you are interested I can email them to you.
Thanks for the compliment.