My interests are primarily food and culture. I would of course love an area with natural beauty or beaches but as I won’t have a car I suspect many of the more low-key places will be difficult to access.
I tend to like cities that are the 3rd or 4th largest in the country; there is public transit and it’s easy-ish to navigate, but not overrun with tourists.
Separately, I’m curious as to Vietnam - how long does the visa take to process approximately? I’m a US citizen if that matters at all.