The ER-6N is just the Ninja without its clothes. The ER-6F is the Ninja 650R in this part of the world, so your post is a little confusing.
Plenty of long distance farkles WRT luggage, better tires, tip-over protection, taller screens, etc.
I had a pleasant 25k miles on my '06, lots of 700 mile days, one over 900. That was with the Kawasaki OEM +1" seat, more comfy than stock.