[QUOTE=skidder13;300 Laying in a ditch all day [/QUOTE]

Mainline pipelines aren't built in a ditch, they are welded on skids on the bank.
Tie-ins/test headers/ect ARE made in the ditch.

Anybody that fancies a life on the pipeline (in the United States of America) is best (by far) served to work as a welders helper and learn the terminology and what's expected of the welder.
From there, the progression to welder is only hindered by your ability to weld to the requirements in the short time alloted.

So the real answer is, hire out as a helper. It's certainly not for everyone and first hand experience will reveal that to you.