Dang. Sounds like some of you guys are troopers. About 6 hrs in the 182 and I'm toast. And I don't like to fly more than 3 to 3.5 hours without a break to straighten out my back. Tulsa, OK to KOSH is the most I've done in a day at around 6 hrs flight time with a stop in Mexico, MO. I was pretty much ready to be done after the fairly wild Fisk arrival. The trip back was the same, but I was worn out from a few days at Airventure.
I'd guess flying in something with auto pilot might make long legs more enjoyable, but I've never flown one with AP.