Doable, but depending on the specifics, you've got the very real chance of having to waste time dealing with broken stuff, the inconvenience, and then you get into the whole quantifying the enjoyable tactile experience.
Sure, as a real foodee or someone who loves to cook, you can use a crappy knife or peeler or whatever, a musician can play a crappy instrument, etc etc but will you enjoy it if you are aware of said crappy item?
Up to you in the end.
but within reason, a cheap bike can be ok.....just depends on the bike.
It doesn't just depend on the bike, it also depends on the rider and their expectations.
I didn't say it would be my choice of ways to tour, but it is one way and the guy I met seemed to be having a great adventure.
I'd rather not ride junk, but on the other hand none of my bikes are high end either. I figure that once you get to a pretty modest price point the bikes can be pretty good. Something in the $600-1000 range can be quite functional and not really compromise the touring experience much if at all IME and that is buying new
My Japanese friend had something that may have been somewhat similar to the "
Walmart Beaumont City Bike - 7 Speed". it is currently listed at $350. It was probably cheaper back then (2011). His may have has a double crankset (not sure), but was probably still limited gearing wise. I don't know if he needed to walk any of the steepest climbs or not, but if he did I doubt he was worried about it. He was of a mindset to just take stuff in stride. Looking at the bike it really looks like for what he was doing it would be reasonably functional. You'd want to have the right mindset, but he did. I'd rather spend more even when doing what he was since my budget would allow it if I wanted to, but I can see someone spending less.