Sounds like a good plan. I also made a windshield for touring and was glad I did. As for an Iron Butt at 100mpg, that would make for a long day staying under 70mph to fit the 24-hour requirement (unless you have a streamliner...)
I did my Iron Butt from Yellowstone NP to Stillwater MN with about 1/3 highway and 2/3 interstate. It was about 17 hours with rest breaks, and every bit as comfortable as the IB I did on my VFR.
I did my Iron Butt from Yellowstone NP to Stillwater MN with about 1/3 highway and 2/3 interstate. It was about 17 hours with rest breaks, and every bit as comfortable as the IB I did on my VFR.