That Scattante still has pretty low handlebars relative to the saddle. You can adjust them higher with an adapter, but the looks &/or feel may not be to your taste. The Trek probably has a lot more room for adjustment, assuming it's the standard 1" threaded with a gooseneck stem. Maybe you can ride a 600K with the amount of drop that the Scattante has, but if you were on the Trek and you got halfway and started having neck problems, then you could stop for thirty seconds, raise the stem to the maximum, and be on your way. (If the stem on your Trek doesn't have enough travel, you could replace with a Nitto Technomic that would provide a wider adjustment range).
When comparing weights, are you being careful to keep the same setup between bikes? 27 pounds for the Trek sounds a little high for a "bare bike", based on my 1984 Trek 400. But with fenders, rack, lights, etc my Trek is probably around 27 or 28 pounds. If you strip both bikes down to just the frame and components (no wheels, saddle, pedals, racks, etc), I'd be surprised if the weight difference between the Scattante and the Trek is as much as three pounds. The weight difference between the aluminum bike I used to ride (Novara Gran Fondo with fairly fancy aluminum) and my Rambouillet is 1.1 pounds. Since the wheels and luggage methodology that I use depend on the brevet that I'm riding, and the saddle and pedals are always the same weight regardless of bike, it's easiest and appropriate to compare the bikes when stripped down.
I sure like riding brevets better on my steel bikes than I did on my aluminum bike. Even with 700x28 tires, the aluminum feels more buzzy than steel with the same size tire. Maybe if I had known about riding on 700x32's I'd have been happier with the aluminum. But that frame eventually cracked and got replaced with steel.
I'm in the DC area, too. Will you be coming out for our brevet series? Lot's of people here ride without fenders, but most of the "hard core" randonneurs ride with fenders unless there is zero probability of water on the road.
I assume you've come across our website at
www.dcrand.org
Nick