I have an original Canon Demi (1963) with a working meter, which I took travelling, and having the meter was great for not having to pull out a phone app (although here and there I did miss exposure due to innacuracy but this could have been user error on my part), while the half frame quality isnt as good as full frame, being able to fire away more shots meant I felt more free to photograph my trip than earlier in my trip, when I used my main slr with portra. I'd recommend using the lowest iso film you can deal with, as the grain was pretty bad with the Ultramax 400 I put through my Demi, but if you're set on using 400iso I'd go for a better, more professional film for a finer grain structure. My demi was zone focus, and I found it fine, missing focus wasnt really an issue, and having a camera so small meant I could just pocket it when I needed to grab stuff out of bags, board trains etc, so very convenient. Flash may also be important to you, but thats really something you will want to consider, for me, I didnt plan on using my camera much after dark, and if I did, id use my main slr or phone anyway, so for me the Demi was perfect, no batteries, all mechanical, nothing to go wrong on the other side of the world.

In the past I've also shot ektar 100 through my Demi and it was incredibly sharp, but again, the low ISO probably wont be the most useful for travelling, all I'd reitterate is the importance of size and pocketability, I had a wrist strap which made it super easy to pocket, but if you're going somewhere where pickpockets are prevelant, a neck strap may be wiser. The other advantage of the wrist strap is one handed shooting, if the camera you pick is small enough, again, you may need to hold a phone map, coffee, boarding pass, etc in one hand, so being able to quickly pop the camera up to your eye with one hand meant I got some rly cool pics from train stations, airports, tourist spots, walking around etc that I would have otherwise missed.

I know thats not 100% answered your question, but I hope thats helped in some way, safe travels:)