One suggestion I have is to shift up a gear occasionally, especially if the road is rough. This unweights your behind. A lot of people use aero bars for comfort, and that has appealed to me. I think arms and hands are the biggest problem for most long distance cyclists.
But we're all different. Don't let anyone talk you out of a suspension seat post if you want to try one. People hate on suspension stems, but companies keep popping up to try to sell them. So someone might get it right. Just because nobody is using them doesnt' mean it will not work for you.