Yeah, seems I've lost about ~5mpg so far since summer on the highway! Temps outside were ~36*F in the morning and probably around high 50's to low 60's arriving at the destination. Another thing that hurts is on some hills, I had to get down as low as 2nd gear to keep going! Long, steep hills are not an Insight's friend, for sure... but still probably gets better MPG than anything else on those same hills, so it's not a complaint.
lol
Just wait till it starts getting into single digits and lower... You can it, throw it on a shelf, and call it "MPG-be-gone".
Outside of my knee locking up (from holding the throttle pedal the whole time without moving it), the Insight was more comfortable than most cars I've driven in such distances/time. I do have a small lumbar support pillow, which I believe helps as well. If my back or tail bone started to hurt, just had to stretch my torso around while driving and all was well. So, for those of you who haven't road tripped much in the Insight, you have my thumbs up on the stock seats!