Performance has Forte-branded insert bike shorts that are meant to be worn under cargo shorts or anything else you'd prefer ride in, for touring and commuting. I bought a pair and it's a pretty good solution for me. I've become accumstomed to the tight fit of cycling shorts, but I also want to be done wandering around in public in lycra :-)
I also purchased a closeout pair of J&G touring shorts from ACA that are very lightweight, almost like a bathing suit. I haven't used those for a long ride yet, but I'm looking forward to trying them.
More than saddle fit, I find that getting shorts/chamois to fit properly is a bigger comfort issue on long rides. And that was true for me even before getting my first <insert happy sigh here> Brooks saddle.
Ken