Depends on if you are going off the beaten track I guess, but without it you are limited to a small range, not ideal.

If the Vstrom had a 30lt choice, that is what I would get, so my advice, get the bigger one

fuel bladder
 

If anyone's interested in one of these, I have got one to sell - pm me-

http://www.horizonsunlimited.com/hub...2-3#post293440

They roll-up nicely. Not as cheap as a plastic bottle but tough and can be stored easily until needed. Think of it as about 100miles in a shot.

fuel
 

You should be OK with your fuel capacity , a flex fuel container is a bit expensive but a great option , depends on you plan to ride but I did similar route few time on different bikes and you always can find fuel , just make sure that if you venture off road you have more than what you think you need ( one can get lost) You can also buy some metal container in camping store , they sale for $15 for a liter and are very resistant, they fit in tube tool and can be carry on the bike very safely.