I have the same issue with my 67 Belvedere wagon. I need to do something about a right rear quarter that on a wagon has the spare tire well. The bottom of the tire well rusted and a previous owner slapped some fiberglass and body filler over it. As for my suggestion for a color for yours, I would suggest medium tan metallic or medium copper metallic. Both are great looking 1967 colors and neither are dark colors. The medium copper is a one year only color. As for my wagon. it has blue interior, so I will either keep it white or go with a midnight blue metallic. Since I have a white 68 Barracuda and a white 66 Sport Fury, I really don't want to keep the wagon white.
The Belvedere I sedan in the photo is medium tan metallic. The GTX is medium copper metallic (the sedan and the GTX are cars I photographed at Chrysler Carlisle).