We sold all our stuff in Oct 2021 and have been doing the slow travel thing. Well, sorta sold our stuff, our "horde box", as your sister put it, is at the in-laws. Just like you, we do 1 personal item each (some budget airlines call it a carry-on). If we are taking a train or bus between locations sometimes we take a grocery bag full of our expensive food from spot to spot. I mostly agree you can get everything where ever you go. I have been a coward about ordering stuff online and having it ship to where I am staying, so I normally go into shops and get something that is
good enough or
slightly overpriced. It is way easier traveling light, and in our opinion, the downside of having to wash your clothes in the shower or sink is worth it.
We are currently in Malta, which according to Nomadlist is "Too Expensive"[1]. The speed you travel REALLY affects cost. If you are getting monthly rentals and cooking most meals yourself, it is very reasonable. Malta is 10-20% CHEAPER than Denver in our experience with both places.
Let us know how your Euro Rail pass works out. Curious about your experience and its cost efficiency!
We had to get covid tests between Mexico and USA, but in Europe, it seems like we just show our vaccination card and are good to go. YMMV
I might be setting myself up for sadness, but I don't do the money belt thing, I do a wallet in my front pocket. I assume my wallet will get pickpocketed, so I keep it light on cash and don't put all my credit cards in it. From a pragmatic worst-case, someone could hold me up and gun/knifepoint on a travel day and take my wallet AND backpack. If someone is going through that effort I assume they are going to ask to see my undershirt money belt.
[1] -
https://nomadlist.com/sliema