I did 3500 miles over 6 days from florida to kansas and back on my bonnie with M bars and small saddle bags only holding rain gear and 2 changes of clothes. The longest I had ridden in a stretch previously was Sarasota to tampa (75 miles). My trip was the most memorable experience of my life and though a Harley may have been easier at times, I was blasting past them in the mountains and would not have traded for anything. Pain is temporary, the memory will last forever.
Yes, you will need to stop and stretch every hundred miles, and yes, if you go for 2 days, that need to stretch will decrease to 50 miles, but it is possible. You will never know unless you try, so go for it. The worst case scenario is you get tired and rest more, but you should have no problem with 250-500 miles a day if you enjoy it.
The anti-monkey butt / baby powder is a good idea before starting to avoid any rash or discomfort. Also, wear ear plugs. Get the $10 ones that mold into your ear, not the cheap neon concert ones you stuff in your ear. You will know why after the first day if you don't.
Do yourself a favor and take the back roads if you can. It may take a bit longer, but you will experience more and enjoy the ride more. The wind on the interstate is tiring, but the Harleys hardly notice it because they weigh so much.
Have fun. Once you take one long ride, 200 miles to get lunch is nothing
