Many of you make me look like a homebody, as in never going anywhere. We do almost all our camping 20 minutes away. Every other year, my Dad and I drive 5 hours down to the Outer Banks for some Father/Son surf fishing (an awesome trip even if we don't catch very much). Then weekend before last, my wife, son and I drove 5 hours to the mountains for a one-nighter. We were on a mission for that one. Camping was not the primary purpose.
On the few long distance trips we've taken, I set the cruise on 62 or 63 and just roll along. What I have found is that the trip is relaxing. Almost everyone passes us in the fast lane, and I have to slow down for very few people. I will admit that merging traffic is a little more of an issue this way. If I can't move over, the mergers have to contend with a 47' rig. I don't slow down if I don't have to. They have to step on it or slow down to merge.
If we traveled like some of you do, I might see things differently. We have a 1/2 ton Suburban and a conventional WDH setup. If we had a 3/4 ton or 1 ton with lots of margin, a Hensley or Pro Pride, and LT tires on the trailer, I might be more willing to roll with the pace of traffic.
On our mountains trip, we were passed by almost every truck/trailer camping rig, some really moving along. I wondered then how many were set up really well for 75 or higher speeds should something go wrong. If you're set up well, no problem. But there are a lot of people who don't understand physics.