Working remotely in the summer (MSc)

I don't understand why this is an issue. You can do mathematics anywhere. The same is true of other fields as well, though maybe not all. All you need is your mind and possibly a bit of paper to write on. You can use a commute to develop ideas, or to rest your mind.

There is nothing, really, in the air near a university that makes thinking easier, though interaction with other people usually helps.

But, as a newcomer, assuming that is your position, you need feedback on your ideas. That can be done remotely, nowadays, though your proposed occasional meet ups will also be beneficial, provided you use them for that feedback.

Being seen has little value in mathematical development. Producing something worth reading will be more valuable in your career than just "being seen". If your advisor agrees, you can share your work at any time via the internet or email.

Note that some researchers carry on collaboration remotely for years, not just a few months.