Not dreaming too big at all.
It will probably take more than a 1 year technical diploma to give you the skill and experience to get out on a pipeline... But it's not impossible, especially if you get to know a pipeliner that might need a helper. You can certainly obtain certifiable skills in several processes in a one year program... You can discover if you like/love the trade. You can get enough in that year to land a job in manufacturing or construction (you may need to leave Michigan).....
Entry level wages in manufacturing go from about $11-16 per hour for somebody without job experience, and a good welder can get raises pretty fast sometimes.
A good thing to do would be to talk to *several* of the program instructors at the college your looking at... Spend some time in the lab and see if it looks like something you want to do. They will know about local job prospects and wages.. If your not welcomed into the lab and given answers to all your questions... Look someplace else for the training.