No matter how the strings are handled that's still a quarter of a million lines of text.
Was this really the intention? I would have expected something like
which writes each player's data once, to the stream indicated in p\stream.
Was this really the intention? I would have expected something like
For p.player = Each player WriteLine p\stream, p\x#+","+p\y#+","+p\z#+","+p\rot# Next
which writes each player's data once, to the stream indicated in p\stream.