Transfer a struct's data to an external struct via serial?
I think you are over-complicating it to send two bytes. Just send them as straight ASCII with a newline after, and decode it on the receiving end.

eg.

42,87


However if the question was just an example of something much more complex, then you may need to do more work. You need to have the receiving end know when a packet of data starts, and ends, and preferably have some validation that it wasn't corrupted.  If you want to pursue that idea, see my thread about sending data via RS485 which has a library that does that sort of thing.