The problem with understanding Charley Patton is that clear enunciation was not part of his vocal aesthetic. In other words, he mumbled. Another problem is that he rambled a lot (didn't stick to the original theme of the song).

"Revenue Man" is one of a number of Patton songs that use the same basic melody and guitar parts. Some of the others are "High Water Everywhere" (2 parts), "Bird Nest Blues", "Screaming and Hollering The Blues", and "Moon Going Down". The last two are my favorites of the bunch. I suggest you try and listen to the others also. Music (guitar tab) and some lyrics are available in Steffan Grossman's "How to play Delta Blues Guitar" and Woody Mann's "Anthology of Blues Guitar" (Both by Oak Publications, I believe). Also this and the other songs are on the double album "Charley Patton, Founder of the Delta Blues" on Yazoo Records (I've got the LP but it's probably available on CD) which has the lyrics on the liner notes. I'll try to find it and verify the following, but chances are whoever wrote the lyrics down had just as much difficulty as you, I, or anyone else, understanding them. Meanwhile, here's my interpretation of them:

REVENUE MAN
Charley Patton

Oh the revenue man is riding, boy you'd better look out.
(Ah, sure, it ain't purty)
Ah the revenue man is riding, boy you'd better look out.
(Boy these horses you don't stop boy)
Every horse you don't stop you will likely be knocked out.

Oh Doll looks at water well she always wants a drink.
(Got to have a drink)
Ah, Doll looks at water she always wants a drink
(Boy, if they see you with a bottle, though)
If they see you with a bottle they will almost break your neck.

Oh, takes me home to, lord, that shining star
(Ah, sure)
I say takes me home, to that shining star
(You know, they ain't no tellin', daddy--Ah sure)
She don't need no tellin', Daddy will take you in his car.

Oh, come on mama, let us go to the edge of town,
(Ah, sure)
Come on, mama, let us go to the edge of town,
(Babe I know where there's a bird nest builded)
I know where there's a bird nest built out on the ground.

Oh, wake up every morning now with the jinx all round my head,
(Ah, sure)
I wake up every morning with the jinx all round my bed,
(You know I had 'em jinx every...)
I have been a good provider but I believe I've been misled.