When I lived in Nottingham I made an annual trip around Scotland on the 916,I also made a point of only taking what I could get into a small backpack bungeed onto the pillion seat.
The average mileage of this was about 1200 miles,personally I found the bike quite comfortable(more so than my current monster) though it could be a trial getting on and off when your tired as a tailpack raises the back to 'can-can' heights.
On all of these trips I never had any mechanical troubles, but that could be due to looking at my prospective mileage and getting any servicing etc. done before setting out.
Cant recommend it enough to all you southern types who are looking over the channel for some sort of biking shangri la.