I use a tool called 'TExtractor' for these places in game. It's an external utility for RPG Maker games to extract dialogue boxes content and send these to Google Translate (and display the result). Lona RPG covers the whole window and is always on top, so you'd need a second monitor for that to work. But other than that, it works decently.
Viewing post in Some places in the game without translation.
Just curious, why would you even do that? The official tool is the same thing but better. It would take less than a minute or two to set up and machine translate the files, all at once. It's essentially doing the same thing as google translate, with no long winded setup and no using that awful program (I've used TEXtractor in the past, I decided it wasn't worth even playing the game I wanted to), and you get to see the text in game in the dialogue box without any waiting for translation.
I simply don't know how it works. I'm afraid it will replace all the text across all of the game including manually translated sections, not just in a few select untranslated places.
Another factor is I use it for all the games with the same problem, so it's a hassle, but not a critical one. If the official tool was not harming the original content, I'd like to try it out, but otherwise it's better to use TExtractor.