As someone who has seen literally thousands of resumes and hired many many people I think I may be able to give you some ideas.
First: Remember that the resume is a tool of ELIMINATION. A person sits at their desk with a number of resumes in front of them and they first start to ELIMINATE some of them. They NEVER dip down into a stack of resumes and Pick out one and exclaim...AHA!
The key is to not be eliminated. (more on that in a second)
You have to look at the specific job you want to get workamping and then write a resume for that job.
Think about all the skills you have acquired over your life; were you in the Service? (leadership) were you ever in the Peace Corp? (Leadership, Teaching, self reliance.) Teaching: (Organization, scheduling)
What specific mechanical skills do you have. Can you do electrical work, plumbing wood work? If you are a Mechanical designer you are probably pretty mechanically inclined.
Stress any supervisory skills you may have.
I would not concern myself with a listing of jobs nearly as much as I would highlight my skills set.
Generally these jobs involve working with the public. So stress any experience you have and accomplishments in dealing with the public or public relations.
Sit down and make a list of these or similar things.
Make the resume readable, NO MORE THAN ONE PAGE you are not applying to the Fermi Physics lab here.
And if you have traveled extensively, dealt with people of other cultures, done business overseas, these can all be highlighted in ways to show that you have the skills to do the job.
Now for the elimination part: If you have done something extraordinary, like the Peace Corps, put it at the top of the first paragraph. Catch their eye..give them a reason to want to talk to you.
My Time in the Peace Corp in the '70's has probably gotten me more interviews than all my experience put together.
And for these kinds of jobs I would abandon the traditional resume format (job by job listing) and head paragraphs with experience or skills headings. Then at the end put in a short list of the most important and long held positions you have held with just the year dates on them.
Good Luck and I hope this has given you something to think about.