I went from Des Moines to Los Angeles & San Diego last fall on a work related trip. I sort of took the long way. About 2,400 miles in 3 days on the way out, 2,300 miles on the way back. I learned a few things, DON'T buy an aluminum sprocket. It can go from showing a little wear to no teeth between San Diego and Winslow Arizona. (Thanks again Fast Eddy.) I've never gone more than 970 miles in a day but I have 56,000 miles on the 2003 TBA in seven years. That's living in Iowa and having four months of really crummy riding weather. The bike has never failed me (Stupid sprocket excepted.)
I regularly take 600 to 750 mile day trips. I usually go onto reserve between 145 to 150 miles running 70 to 75 mph and assume another 20 miles after that. So far so good, never had to push the bike or hitch hike.
As for handling, we won't keep up with the sport bikes if they push too hard but the tourers won't leave us and other cruisers can't keep up.