The station is a feeder location and the belt is shaded outdoors. I do not know about FT, but they hired PT off the street when I was there for another company. FedEx would be one of the better jobs in Yuma, so my guess would be higher seniority people probably stick around.
The area is linked with Imperial, CA which I think is also a small feeder location. It's about 45 minutes of easy interstate driving in the short-term if there was an opening there, but not in Yuma.
IMO there is little to do in Yuma. If you like sand dunes and the river it can be an ideal place. I knew people that preferred it over San Diego. San Diego is about 2.5 hours and I had employees that went to Tijuana every weekend.
There about 100,000 people in Yuma and they get about 100,000-150,000 winter visitors and migrant workers in the winter from October/November-March/April. My guess is there is quite a bit of seasonality. There is lots of agriculture and military (there is a MCAS and an Army proving ground).