This song is pretty much exactly the same as Subterranean Homesick blues except for the 
blues has E/Em, Am7, than Bm) Just capo the third frett and it should sound like the recording.
There are various riffs in the key of G everywhere in the song, that I'm too lazy to tab.
The other tab is almost correct, but shows none of the minute hammer ons that Dylan 
the G/Gm chart below),
plus there is no Em, it is Am(7)

Here's a little activity: Listen to the first few seconds of Homesick Blues and
than the first few seconds of Maggies Farm. Notice the easily recognized similarity :D

G/Gm                Am7                  D
=============      =========           =========
--0---0---0--      ----3----           ----2----|
--0---0---0--      ----2----           ----3----|
--0---0-h-1--      ----2----           ----2----|
--2---2---2--      ----2----           ----0----|
--2---2---2--      ----0----           ---------|
--0---0---0--      ----x----           ---------|
=============      =========           =========

G/Gm
I ain't gonna work on Maggie's farm no more
G/Gm
No I ain't gonna work on Maggie's farm no more
G/Gm
Well, I wake up in the morning, hold my hands and pray for rain
G/Gm
I got a head full of ideas that are driving me insane
       Am7                                   D
It's a shame the way she makes me scrub the floor
  G/Gm
I-- ain't gonna work on Maggie's farm no more

I ain't gonna work for Maggie's brother no more
No I ain't gonna work for Maggie's brother no more
Well he hands you a nickel, he hands you a dime
He asks you with a grin if you're having a good time
Then he fines you every time you slam the door
I ain't gonna work for Maggie's brother no more

I ain't gonna work for Maggie's pa no more
I ain't gonna work for Maggie's pa no more
Well he puts his cigar out in your face just for kicks
His bedroom window, it is made out of bricks
The National Guard stands around his door
I ain't gonna work for Maggie's pa no more

I ain't gonna work for Maggie's ma no more
I ain't gonna work for Maggie's ma no more
Well she talks to all the servants about Man and God and Law
Everybody says she's the brains behind Pa
She's sixty-eight, but she says she's fifty-four
I ain't gonna work for Maggie's ma no more

I ain't gonna work on Maggie's farm no more
I ain't gonna work on Maggie's farm no more
Well I try my best to be just like I am
But everybody wants you to be just like them
They say sing while you slave, but I just get bored
I ain't gonna work on Maggie's farm no more