Worth it carrying spare spokes? Truing a wheel and lacing spokes is a big deal, requires a truing stand and everything. I know some do it without tool just with the spoke wrench and the naked eye, but feels like a big deal to me.

When one breaks a spoke, I believe it is safe to say the wheel is out of true within a few meters.

The question therefore is: is it worth it carrying spare spokes when touring longer distances (200+ km)?
It's pretty easy/light to carry around a couple extra spokes per wheel and a pretty good idea for a long tour.  You'll probably need a few different lengths though for the front, rear left, and rear right sides. 

Another good option is to carry an emergency fiberfix spoke that can be used with most wheels, which will help in an emergency.

http://www.amazon.com/FiberFix-Emergency-Spoke-Replacement-Kit/dp/B001GSMQZC

You may want to work on your skills with truing a wheel without a stand as well. You can use a couple zip ties on your seat stays in place of a truing stand. Just make sure you are comfortable with this process before you go on the road, and don't forget your spoke wrench.  You may need a cassette tool / chain whip as well if you need to replace a spoke on that side of the rear wheel.