Last year I worked for a land trust on putting together a feasibility study and preliminary planning process to develop a new (to them) property for multi-use recreation. I spent most of my summer wandering back and forth over 1200 acres, taking notes, GPS points, making maps in GIS, pictures, laying on trails on both maps and on the ground. My average week was 20 hours at the land trust and 10-15 doing catering (which I had been doing for years). It was very rewarding, but they only had about $2,000 in the grant to pay me, and by Fall I had used most of that up.
They offered to let me work 8-16 hours a week, but had no full time position available at the time.
I looked for jobs in the area, but my romantic interests required (hehe) that I move 6 hours away.
In this new city, I found jobs quickly, and networked enough to apply for two related positions to what I doing back home...but I was unexperienced and didn't get offered a job.
Now I'm doing 8hr work that has nothing to do with my career just to pay the bills.
The land trust recently gave me a job description for the same job I was doing last summer, and they haven't posted it publicly yet. They made a job for me! Woot!
My question is, do I write a cover letter explaining why I went 6 hours away when I was offered some minimal hours to stay there and work? Or do I avoid the cover letter and just go straight into the roles and skill that I demonstrated last summer (which are exactly what the job description requires)?

