Road trip, long trip, you're in no hurry, but you don't want to take forever either. Pretend there's no speed limit, like the autobahn or autostrada (but not) - how fast do you drive?
55 it's the most economical and I'm a bit of a tightwad!!! Plus I can look around and not really pay attention to the road!! Unless I was driving to see you though, then it would be "pedal to the metal" time ;-)
I'm on vacation. I drove up north - it's a 10 hour drive. I passed, maybe, a handful of vehicles along the way, and I drive between 65 & 70. So I was just curious, without a 70 mph limitation, how much faster I would've been getting passed.