I thought I'd give a brief update to this story.
After a few weeks driving the dually, it's no longer an issue to drive or park. As long as you find a good spot, or take up two when it's extra tight.
I have now driven over 13,000 miles and have been on many types of roads. By the way there are many bad road's through the US, and there is nothing to prepare you for when you hit a bouncy dip in the road towing at 65+ mph. It's times like these that I'm glad I have a dually. Even with the occasional very bouncy bump, I've never felt like the truck was even close to being out of control.
I've only had to stop once or twice towing up mountains (to cool) as well as slowing down to about 35mph and that was up the Rockies. Otherwise there has been plenty of power from Utah to DC. A few miles of 7+% grades are fine, but 10miles etc of 5+% gets the heat up.