Ronnie Van Zant wrote "Freebird" with Gary. Lyrics and notions are all original to him. The whole song is very inspired, Ronnie really put his heart and soul into it.
It is a very empowering and exciting song, but three guitars screaming at you for upwards of 8 minutes will do that. Skynryd was actually a really complex band as far as having a bunch of musicians all playing at once. You have three guitars, bass, piano, harmonica(occasional), fiddle, trumpets(occasional), backup singers, and a singer.
I grew up in the same area Skynyrd did and played in Jacksonville. My father and grandfather know their families and played with several members in little bands before they were Skynyrd.