Dougy Drums, In addition to Sforzando PG Music includes the free version of
+++ Synthfont 2 +++ with Band-in-a-Box. Synthfont 2 is a multi timbrel midi player so one instance of Synthfont 2 can play more than one instrument. PG Music also includes a GM compatible instrument patch.
I'm not sure that's quite right. PGM certainly includes VSTSynthFont (VSTSynthFont64), from the same people, but I think not SynthFont2, though do correct me if I'm wrong.
I have to say that I find synthfont's website very confusing. Too many applications with names too similar to each other.
The BIAB manual page 9 tells where to find it (bb/Data/libx64) and how to install it.
There are better soundfonts than the default one that comes with it.