I have no clue why you would have chain rubbing on the frame. If you have not touched up the paint on the frame, I would do that first. I use fingernail polish for that sort of thing, the brush being built into the cap makes it very convenient.
I agree with previous comments on the rims, my only additional comment would be to keep using them as long as you can, I have virtually no wear on my CSS rims and am very happy with them.
Front wheel spokes, it is very rare for a front wheel to break spokes, rear is much more common. And to break two, that suggests that the third and fourth broken spokes are coming soon. I do not know if you have a dynohub you want to keep or not, but I would suggest retaining your existing CSS rim, have a wheel builder replace the spokes.
If your front hub is a non-dynohub from Shimano, they were often skimpy on grease, would not be a bad idea to open it up and add grease.
You did not say where the spokes failed, if I recall correctly several years ago there were some bad Sapim spokes that failed by breaking in the middle and not on an end, if yours broke in the middle, I would most certainly replace them.
If you do not have a dynohub, but if you might want one some day, now would be the time to add it if you replace the front spokes. Dynohubs do not come with a skewer, retain your old one.
If you replace your front spokes, I would just buy a couple spare spokes and discard your old spare front ones.
If your next trip will put you far away from bike shops, after over a decade of use you should make sure that the bearings in your bottom bracket, pedals and headset feel as good as new, if unsure replace.
If you have Shimano pedals, a lot of their pedals can be disassembled with the TL-PD40 tool. If you have pedals that use that tool, as a preventative measure I would remove the spindle from teh pedal body and add some grease. But do a thorough cleaning first. The tool is very affordable, there are several good youtube videos that explain how to use it. I have found it very simple to remove the bearings, add grease and close it up again. I had two pairs of pedals that developed a clicking sound, but all they needed was additional grease.
https://www.youtube.com/watch?v=bVmSrsnVUGISide note: Park Tools have excellent youtube videos if you find you suddenly need to figure out how to fix something.
I do not know if your eccentric uses the same screws as my Nomad Mk II to keep the eccentric in place. If it does, I found it useful to put a couple of rubber bands between the two screws, that way they can't come lose and unthread from vibration. See photo. The rubber bands were cut from inner tube rubber, that seems to last longer than normal rubber bands. But I still carry a spare screw on tours, it is a very odd size and would be hard to replace.