Yep get a 32t or a 34t for your tour and hang on to the 38t ring for when you return and ride with less load at home. See if you can work it out so one chain length covers both if not it’s not a big deal to swap chain and ring when you tour.

The questions and solutions about the RD were very interesting. If you can post some photos of how you end up doing it after the switch. I think many people myself included would love to see the finished product. Before and after.

Good luck.