Hi Sheerblue,
Thanks for sharing your situation. It's difficult, but you have options, so let's explore them.
First, let's list the positives of your situation:
1. Not tied down by anything (home, relationship, family (assuming that your children are self-sufficient in college)). This is actually a big deal. The only person you need to look out for is yourself.
2. Previous experience with construction/welding/boilermaking/etc.
Now let's list the negatives of your situation:
1. Instability in terms of living situation and job.
2. Lack of vehicle and formal education.
Let's look at how the positives work with the negatives, and what changes can happen to improve your situation.
First, the fact that you're not tied down by anything means that you need only provide for yourself. So your needs are, really, just a roof over your head and food and water. Of course, in the long term you will want more, but in the short term, all you need is an affordable housing situation. Instead of a full-blown apartment, how about renting a room in a house, or even sharing a room? People in this economy are often inclined to rent out parts of their house to make a little extra money, so you'll want to see what's out there and cheap.
Next, once you have a housing situation scoped out, you will have a number to meet. That number is the amount of money it takes each month to pay for rent, bills, food, water, and incidental expenses. That will be your monthly goal.
To meet your goal, you will need to work. You say that you don't feel comfortable working in construction. However, you do have experience in the industry, and it sounds like you're generally handy. Start thinking of ways you can use this experience without directly working in construction. Maybe you could work in construction administrative support. Perhaps you could work the front office for a welder/boilermaker/etc. Or, if you need money immediately, you could suck it up and work construction, while still looking for jobs in your off time.
The lack of a vehicle may or may not be important, depending on where you live. If you walk/bike/use public transportation to work and your basic needs (grocery store, etc.), then you might not need a car. If you do need a car, find something cheap. If you don't pay for it all upfront, you'll have to add monthly payments to the number mentioned two paragraphs ago.
Without a formal education, you won't have as many choices for work. Depending on time, you may want to look into getting a degree or certification of some kind. This might involve night classes or even full-time enrollment. Of course, education costs money, so you may need to finance it with financial aid, a loan, another job, etc. But it may be a worthwhile long-term investment in yourself. Most jobs that offer paths for advancement require college degrees.
If you need money *now*, a dead end job is fine so long as you don't stop looking for non-dead end jobs.
Another option is work-at-home jobs. There is a forum of work-at-home moms (http://www.wahm.com/forum/) devoted to such jobs.
Your long-situation may seem overwhelming, but it helps to break things down into smaller bits. Your first concern is to stabilize your current situation and to get a consistent and affordable roof over your head.
Good luck!