i found a great collection of cd music of orchestras that played at the grove: phil harris, gus amheim, jimmie grier, and ted flo rito. other than harris i never heard of the other 3, lol, but the music is great. i'm really into 30's music, but a lot of it is new to me, since i was born in the 50's. i don't know if these recordings are old news. i'm not an mp3 person either and don't know if these recordings are floating around in the mp3 universe, but the notes say that the recordings are "nearly impossible to find" or something to that effect. this is an excellent collection of cd's, much better than i expected.
http://www.radioarchives.org/sets/PC70.htm