As far as being comfortable on long rides in the stock seat, do the Hokey Pokey.
Move your whole self forward,
Move your whole self back,
Lift your whole self up,
Put both feet forward,
Put both feet back,
Put most of your weight on your right "cheek",
Put most of your weight on your left "cheek".
Repeat as necessary.
One other tip I've been using for 40 years.
On long trips, go commando.
If you get wet either through rain or perspiration, your underwear will never dry out, causing the dreaded "Monkey Butt".
Also try to remove any wrinkles in your pants that you may be sitting on.
If you can't bring yourself to go Commando, do what Wes used to suggest, wear a spandex type of garment under your pants.
Friction, dampness, and fabric wrinkles are a long distance tourers demise.