Thanks for the suggestions!
I've looked at the Byway in 700c for another bike, but hadn't thought about it here.
I've used many variations of Schwalbe Marathons before, but hadn't seen the Almotion, so that's definitely a contender.
I've looked at Big Bens before, but they seem not that different than the Kenda Kwick 6, though maybe a little deeper tread? Trying to figure out which Kenda I have, though, revealed that they're having a big sale, so I'm off to peruse their offerings next.
Happy to hear any other ideas, too!
- Bruce