Several years ago I showed a substitute for a chain whip here:
Chain Whip for Travel

I just got home from a tour. I carried that chain and cord that I cited above.

I also carried a Unior cassette tool with a vice grip to grip the Unior.
https://www.tradeinn.com/bikeinn/en/...ke-key/1375982

I do not tighten my cassette lock ring as tight as manufacturers cite, I can easily get it off with a 5 or 6 inch long wrench, or for my last tour a Vice Grip on the Unior.

In my case, I do not want to use the Unior tool against the frame or hanger as was intended in the design, as I fear possible damage on my titanium bike with a hanger that looks rather non-robust. Thus, the short Vice Grip.

As noted above, the Fiber Fix is a viable solution if you do not want to remove the cassette. I bought a Fiber Fix for my road bike because I bought that as a complete bike, I do not know the proper spoke length and chose to just buy the Fiber Fix instead of measuring spoke lengths.