This thread has gone from talking about doing an SS1000, to the crap seat on the KLR. And let's just skip over the stuff about the FAA et al; you're talking there about someone (or two [pilots]) managing other people's travel. You ride an Iron Butt - you're responsible for yourself. Assuming no passengers on board.
I've done 4 SS1000's; I've only bothered submitting two. Have a look at the IBA forums to get an idea of what you're getting into. My rides were on a Hayabusa, my K1200RS, and there was one where we swapped (press) bikes back and forth; a K12RS, a brand new FJR13 when it first came out, and a most crappy Triumph Trophy 1200. Temps hovered between 4C and 10C at best. Met up with Mike Kneebone in Chicago at the end of it. All experienced riders,
the 3 of us (sorry, had to relive that again for a moment!!!).
Of course fatigue is involved. You need to build up your endurance abilities, and of course, prep you bike properly. Being fit helps as well.
I WILL do an SS1000 on the KLR simply because it's a challenge. And, the range is just about right for seeing if I can knock it off in 4 tankfuls !!!
1620km total distance, 400km typical range !!!
These rides are much easier using Interstate highways, hence riders knocking them off in less than 20 hours in some cases. Up here in Canada, we don't have as vast a network of highways. Yes, you can do 100km/h in many 80km/h zones, but that's only in the country.
It's not about speed anyway. You need to average 67.5 km/h. Sounds easy, but that's for each and every hour. Anyone in the GTA area, or shall we say Montreal to Windsor corridor, who is interested in a ride around the Summer Solstice of 2019, let me know !!