My viet name has many accent and strange letters, so I just type in the name spelled at the machine reading line. I got approved. I have applied evisa from many countries that way.
I emailed Japan and Germany embassy in Bangkok, and they said I can apply for visa here while on DTV. For the U.S., i think you can apply anywhere regardless of residency location.
You can go to Nha Trang ( beach resort city), or Da Lat ( Highland french vibe city), only 8 hour bus ride or less than 1 hour flight from HCM. I personally can't stay in HCM over a week, too much pollution and traffic.