The actual answer is don't do it without a lawyer. But lawyers cost money, and sometimes people don't have the money. It is hard enough to handle...

Would I have a valid PI case if I was driving the company van on the clock and the other party turned in front of me ?

In short, based on your description, it looks like there is a case. But this case will require some investigation.

Can you appeal civil lawsuits such as custody issues if your the plaintiff?

If this is a child custody case, you can appeal to the Arkansas Court of Appeals if you are unhappy with the result. But reversing a Circuit...