I've personally ridden a 748 mile day on my KLR. Had an acquaintance who had ridden a 1400+ mile day with his 70 pound Labrador.
If you mean how far in a single day on the highway, it's 610 miles from Bartlesville, OK to my house in Houston. I had been ridding on the TAT from Memphis to Bartlesville, OK after X-mas with family. It was 26 degrees New Years Day and I wanted to get back home for the work week.
My longest single day was 770 miles. When I did my ride to Alaska, I regularly did 9.5 to 10 hours in the saddle on most days. Mileage varied across the days depending on the type of riding: freeway, back road, gravel, or off-road. Total trip distance was just under 10,000 miles.
I'm a mechanical imbecile - but I was able to do the Doo in my garage, with my son (who is very mechanically inclined) as my babysitter.Wow... I'm impressed. Actually I was mostly wandering about the longest trip...no matter how many days, but the daily miles you guys put on is a lot higher than I expected. I'm picking up my first KLR, an '03 with 10k miles on it tomorrow. I'd had big plans to have it road ready before I got it with 2 new tires, and having my doohickey and that extra spring installed. I thought from lurking on the forum that the doohickey installation was a fairly simple operation. When the dealer saw the part I gave them, they told me it was a major ordeal, getting deep into the engine and would cost me about $200 labor. When I finally got around to looking at the youtube video I saw they were right. Since I'm out of money, I'm taking the KLR home as-is. If I fall in love with it, I'll scrape together the extra bucks, and have them installed. I am NOT a mechanic. After that, it's the taller windshield, better seat, and distant horizons.