My Iron Butt days were either on a Suzuki GSX 1100 super G, Kawasaki concourse, both with custom built long distance saddles, or BMW K1200LT (also known as Light Truck) so I always had a bike with comfort in mind. Although. The Kawi handle bar geometry was off leaving me with numbness. I'd still be riding Iron Butts, but my vertebra in my neck won't allow it any more.
My best trip was across the high plains. We didn't so that in 1000 miles, close to 400...but to this day, it is still the best trip I ever took. I'm hoping to take my wife of 23 years up there this summer. My only problem, is that I have become quite attached to trees....until you get to the far west side of South Dakota there aren't many of those there.
I'm thinking 2 weeks. North to Mackinaw City, spend a couple days then head west. Well see, I'm still in the scheming stage of that plan. But I'm thinking home to mackinaw, to twin cities (with a quick stop in Necedah. To say Hi to the Becky and the camp-inn guys), then to Wall or rapid city area.....spend a few days in the badlands, then out to devils tower before heading home via Kansas City (Strouds family restaurant calls!!!!)
Long trips and meandering used to scare me, so I appreciate the concern about a family moving that distance, but cell phones and ham radio do a lot to increase safety by giving good communication. It's not like the days of Horatio Alger when a minor problem could spell death.
If I can't do that, I'll reserve time in the great parks here in my home state. Either way, I win.

. We are truly blessed in Indiana with some great places to stay....Tuekey Run, Brown County, and Clifty Falls to name 3....