As an engineer, is there anything you could do from a computer? Is there consulting work you can do? You might look at changing things up a bit. Are there companies that just need help on special projects, maybe for a couple of months at a time? I am completely guessing, but sometimes it takes looking outside the box to do what you want. My wife and I and our four kids currently fulltime. I work in healthcare, so I joined a travel company and do 13 week assignments in different places. My wife works as a virtual assistant, so we can stay mobile. We did sell out to do it, but it's only stuff and can be replaced if I want more.
If you want it bad enough, you will find a way to do it. Good luck, and happy travels!