All good comments mentioned here so far. Other than clothing gear, I try to focus on the simple things I could fix on the road. I think about the little things that might happen to my bike and try to prepare for that. I am mindful of the fact that unlike some other bikes, there is not a dealer for parts and repairs located about every 30 miles away. Anything major, call your good road service company.
I have a copy of the pdf service manual on my phone and a good image of the electrical circuit if you are comfortable with that. How about the android Tuneecu and a bluetooth OBD device for checking codes if you get one. You might also consider an extra throttle grip, a front disc lock, a spare throttle and clutch cable, a short length of electrical wire and scotchlok connectors, some lengths of electrical tape I have rolled around the circumference of a dowel rod and a compact multimeter.
What it boils down to on parts is.....I can replace a relay, replace a cable, replace a grip, clear a code, bypass a switch, and try to fix a simple flat. Anything else, I'm stuck.