From the Sam Rizetta album I mentioned above, here are the original lyrics. Very close to the ones in the DT but with a few minor changes over time. The most major changes took place in the last stanza and in changing the years from 16 to 15. This is my transcription.

MOTHER TRUCKER

Come gather round me, truckers and I'll tell you of my fame
Waitress, pour the coffee, won't somebody pass the cream
Well, a broken heart has brought me to this truck stop here today
A heart that got run over on the interstate highway

It was sixteen years ago today dear mama left our home
Walked out before breakfast, the freeways for to roam
Now they say that ma's a trucker out on that broad highway
Yes, she's put on boots and Levi's, threw her gingham dress away

CHORUS
What made her give up pots and pans for a gear box and a clutch
Leave husband and nine children, and we love her very much
Now she's mother to the truckers as the interstate she roams
But Lord if you love your children send that mother trucker home

Little did she know the dangers as she drove her diesel through
Till she got in a heck of a terrible wreck just outside Kalamazoo
Well, the flames was seen for miles, the streets run red with gore
We despaired of ever feelin' mama's tender touch no more

Three truckers, two state troopers and six cows was lost that day
But thanks to the love of Heaven above dear mama walked away
Now, I ask you hearty truckers, as you drive throughout this land
Should a mother of nine children face the hazards of a man

Chorus (... children, when we love her...)

Now have you seen her, Crystal, tell me have you seen her Pop?
Does she ever stop for a piece of pie down in this old truck stop?
Yes, she's sweet and prob'ly grayer than when she left dad's farm
And a tattooed heart says Father in the crook of her right arm

Now sixteen years of truckin', but I can't track poor mama down
So I only hope she's happy with that rollin' life she's found
But one thing I know for certain, when we reach those pearly gates
Yes, she'll be truckin' souls for Jesus 'cross those golden interstates

CHORUS