Seeing as this thread is close to a year old and he hasn't responded, I'm thinking he probably decided not to pursue it.

 

dagnabbit. suckered again. good catch ia......

 

I'm not going to respond on what bike would be best for long distance, as I've only rode 1 harley (street bob) and while I've done a 5 hour trip on it without too much trouble I am sure there are better options for long distance and that other members can give far better input.
However, a good friend of mine is a left arm amputee below the elbow.
He has a prosthetic arm just for riding, its one of the older models with straps that go around the back, the hand is a hook. He moves his shoulder to bring in the clutch (has tape around the clutch so it doesn't get scratched). He hasn't had to modify the bike (other than some simple tape on the clutch) to get around his disability.
Hope this helps.

Edit: opps nvm, seems like this thread is long since passed.

 

aaaaa

 

I have a 2010 Road King, only Harley I have owned. I live in Texas, I have ridden it to Phoenix, AZ to Sturgis, then back to Texas twice, not stopping other than for gas or food. To me it seemed like a Cadillac. I found myself hitting high speeds not realizing how fast I was going. I have also ridden from Dallas, Texas to Phoenix, AZ back and forth twice. No problems and very comfortable.