Many folks have found their buses from far away. Airplane rides there and drive the bus home. One recently went from, I think, CA to FL, and with no problems!
You're in a good area, dry and hot. School districts are generally required to auction their vehicles. You may want to check with some smaller districts and see how they dispose of their old buses. Might get a good lead. Who knows, maybe some districts still auction them off themselves.
Private schools, I got mine from a Catholic High School, are not under the same government thumb as public, so they can sell direct to a buyer.
Some people who have started a conversion are selling, so you might find a bus already started, but still allow you to make it your own.
More importantly, assuring the bus drive train, tires, brakes and electrical are in good working order is key. Buses are more expensive to fix than to simply by.
Best of luck.