First, thanks everyone for all the input. It's all super helpful and much appreciated.

re: the suggested route: NRT-SEA-PHX-MEX-PHX-SEA-DFW-SCL-MIA-SEA-DOH-BER-MAD-DOH-KUL-NRT, I didn't realize I could go back to SEA that many times. Anytime I included it more than once on the OW tool, it broke so I wasn't sure if it was the defective tool or against the rules. This will be super helpful.

The rough plan is Tokyo in January, Mexico City in February, Santiago in March/April, Europe by way of Helsinki in May, and then back to Europe and on to SE Asia in Sept/Oct. That aligns with the seasonal routes to SCL and HEL and hits some of my favorites times to be in these spots.

And I don't care too much about maximizing miles, probably? I'm admittedly keeping this pretty simple the first time just to see how it works out. I'm sure by the next one I'll be geeking out and squeezing every last drop from my 16 segments...

I'm sure I'll be back with more questions, but again thanks everyone.