Mike,
this depends a great deal on just how much you will carry. But since you said lite...

This is what I do on a sagged trip. I use a Carradice bag supported by a Bagman. My frame is a Gunnar Sport ( wonderful bike, with skinny tires it can hang with most, with medium sized tires you can credit card tour). I use sturdy wheels, 32 spokes. For you I'd suggest something like the Rivendell
Ruffy Tuffy tires, 27c. I used them for years and loved them. They don't need a lot of air; and the low pressure gives them a nice ride.

Other choices with what is now called relaxed geometry ( we use to just call it
a road bike. A racing bike we called a racing bike. It was a simple time.) are the Surly Pacer, Specialized Roubaix and quite a few others.

Another choice if you don't need racks is the Habanero Road. Really sweet riding bike www.habcycles.com

Gunnar is Waterford's 'budget' line. It's really a non-custom base level Waterford with a simple paint job. If you could afford the midlevel or their
top of the line, my hat's off to you. Amazing bikes. But I have to say I love mine.

If you do need a rack, I like my Tubus Fly. It weighs 12 ounces, half a typical rack and a third of what some weigh. It's plenty tough if you aren't throwing 40-50 pounds on them. Had mine several years now, been on several trips with it. I prefer a bike without racks, but if ya gotta have a rack, this is as good as it gets, IMHO.