I think you'll be fine with either, since they are both touring bikes. Go for all-day comfort, whichever one that is. Sounds like this is a one-day thing, so you don't need a tent, sleeping bag, cooking stuff, etc, so you don't really need load-hauling capacity.

NY Biker's list looks good. I don't carry tampons unless I think I'll need them, but on something that long I always need to re-apply the chamois cream, and I always carry lip balm. I learned the value of wipes on a recent ride - don't leave home without them (and the $$, insurance info & ID). On something that long, I like a baggie of gummi bears to make me smile. On a long, hot ride I'd be carrying Heed in the bottles, and an extra baggie of powder to mix up when I'm ready for a refill.

Have fun! Eat light, eat often, and drink a lot!