I would also search up summer jobs on Cape Cod that may also include housing/visa sponsorship. Traditionally there are a larger number of people coming in from overseas to fill those positions. There are trains, ferries, and busses that run to Boston from the Cape, but it may not be what you want if you are looking to live in Boston.

https://www.capecodchamber.org/life-on-cape-cod/working-here/job-listings/cape-and-islands-summer-jobs/