Last weekend my Speedmaster passed 12,000 miles (since November 2005) on a 2-up 500-mile trip to Triumph Come Home. A few weeks back we had a 600-mile trip to Butler's Orchard. Most of those miles were on the slab at an indicated 80+ MPH.
We're almost in the same weight class as you two. We were also hauling saddle bags and a sissy bar bag. We were moving right along and loving it. Very few vehicles passed us. And we were very comfortable with a touring saddle with sheepskin butt pads.
I also use my Speedmaster for commuting, around-town errands and Sunday fun rides.
Look, the Speedmaster & America are middleweight cruisers, and they excel in that category. I love my Speedmaster. I LOVE IT!
That being said, I'm looking at also getting a Victory Vegas or Kingpin to add to the Speedmaster, for more heavy duty weekend or weeklong touring trips. Keep in mind those bikes are in the $16,000 range. The America and Speedmaster are around, what, $9,000? That's a huge difference!
Take some demo rides and test rides and compare.
Best of luck & ride safe.