I rode from Roswell,NM to Locust Grove,Ga(30 minutes south of Atlanta) in 21 hours last year. Depending on who's map you use that is 1380/1340 miles. I rode my 1999 ZX-9R. I did it with a friend that rode his 840 VFR.
It was the saturday after the final AMA round. We left Roswell at 10:00am est and arrived home at 7:00am the next day. I had a case of "homeitis" and was ready to be home. Elvis wanted to stop when it looked like we were going to get rained on but I won. Tip: ask people coming from where you are headed what the weather is like.
On the way out to Pikes Peak I pulled two 800 mile days back to back. Yes, I now know I took the long way.
As far as recovery, the 1340 day I got in the bed about 8:00 after a hot shower and slept until 3:00 in the afternoon. I went to church that night and to work the next day. I really felt cleansed. After that long on a bike you don't have anything else to think about. I had couple of red spots on my butt(duh).
I ended up riding over 5500 miles on that trip. It was the most awesome ride of my life. I used Vanson leathers, Bridgestone BT-57's(over 8000 miles on the rear,still using the front-it doesn't get as much use), Helibars, Throttlemeister, Ventura bike pack system, Bagman saddlebags, Corbin seat, some kind of gel pad and Protek rearsets.
This year with the new BMW R1100RT, 1500 miles in 24 hours will be a snap!
It went...Earth Sky Earth Sky Earth Ambulance.