I've listend to the CD and im pretty sure that it goes like this. The other tab sounded close to 
me but was missing a minor chord.

*capo on 3rd fret*    *intro D,Em x2

    D                                    Em
   We rode from texas, all they way to montana. 
          D                             Em
   Having no idea, what we were getting into.
    D                                   Em
   With a herd of cattle, aross desert sand
    D                                 Em
   Wonderin if, this trail would ever end.
    D                          Em    
   Half way there, i lost my best friend. 
       D                                         Em
   Gusss had to fight a battle he knew he'd never win.

   Chorus:
    D    A               Em     G,G/B,Em
   Liiiiife on this old trail.
    D                            A               Em G,G/B,Em
   I've been through heaven and I've been through hell.
     D                    A                   Em    G,G/B,Em
   Most of the boys and I, have died and gone above.
    D                   A                    Em 
   We should have never, had left lonesome dove.

   intrumental break: D,Em
    D                                       Em
   We finally got there, and settled in the valley.
             D                                          
   With Montana mountains all around, as far as we could 
   Em
   see.
    D                               Em          
   I wish Gus was here, and he was alive.
        D                                         Em  
   To see everything we've seen, and to finish the drive  

   Chorus:2 times played
    D    A               Em  G,G/B,Em
   Liiiiife on this old trail.
     D                           A               Em G,G/B,Em
   I've been through heaven and I've been through hell.
    D                    A                     Em   G,G/B,Em
   Most of the boys and I have died and gone above.
    D                   A                   Em   G,G/B,Em
   We should have never, had left lonesome dove.

    D                   A                   Em........
   We should have never, had left lonesome dove.