Listen carefully and you'll hear Jerry make the A# (the major 7th of B) work in this song as a great passing tone. His descending riff at the end of the song uses this to great effect.
I think this is a classic Jerry mixolydian song. There's always room to push the envelope a bit and throw in arpeggios and bits of other things. In an interview once, Jerry referred to these other bits as pieces of furniture that you can move around.
I use mixolydian all over these solos. It's one of my favorite uses of this mode.