Tool kit.... Cell phone, gold card, auto club card and a flashlight.
Now that I have the joke out of the way, though for some that is all they need.
Your on the right track with your 2 kits. Parts are always a hard one to decide on what to carry. Depends on your room for the trip.
I would pull your bike to your work area. Then look at what you may be able to fix on the side of the road, or even at some sort of repair place. They may not have THE tool you need. Things you might fix, lights, cables, plugs, axle bolts, ect.
Now pull out all the tools you need to fix the things. Screwdrivers, wrenches, allen wrenches and the like. Put them in a pile and see if you can fit them. Then look at substitutes. Adjustable wrench, spark plug socket that can be used with the adjustable wrench, the insert type screwdriver and allen bits and a ratchet wrench and short extension for the bits (HF sells a wrench for this under $5 with some bits). You get the idea. The substitutes may take a bit longer to use, but if space is an issue and your stuck, time may not be an issue.
Good luck on your choices!