My longest single day trek one up on my Speedie was one of around 900 miles from las Vegas New Mexico to Spearfish South Dakota. High Summer hot as can be.
It was a long long hot day but comfortable other than my butt getting numb the last 300 or so miles.
I ripped along from Las Vegas to the pass in southern Colorado @ near flank speed. Used up gas at a frenetic rate on that leg.
IMHO The America and Speedie are outgunned by cruisers with more displacement and comfort featurs for two up long distance cruising. But I know a few here will argue with me on that as long as the day is long.