What do you mean very little without driving o Phoenix or San Diego?
This link lists 5 flight schools in the Yuma area.

List Of Flight Schools in Arizona

I've spent a bit of time in the area and many friends have lived in the area and seemed have enjoyed the QOL.

Buy a house with a pool, enjoy the water sports ofvthe Colorado River, or turn to ATV fun on the dunes.

I'm not sure what you're worry is with the Marine Corps.

What is it that you are not enjoying about aviation? What is your job in the AD Air Force and what will you being doing at MCAS Yuma?

It sort of sounds to me like if you took the job in Yuma, kept flying on the side, built some more hours/experience, kept the paycheck and benefits son you weren't fiscally challenge during a tough economic time that you just might have good timing for getting out if the 'shortage' materialize.

If you truly dislike your job that much though then your number one concern should be your quality of life, and a person who hates getting up every morning to go to work usually doesn't have a very good QOL and it trickles down to family and friends.

USMCFLYR