A good alternative to wood under the tires and jacks is the synthetic deck material. No rotting, doesn't absorb water, and no insects. You only need short pieces under the jacks, and I got my pieces just listening for the sound of a circular saw in the neighborhood, figuring out who was building a new deck, and wandering over with a couple of cold beers....
2014 RAM 2500 Laramie 4x4 Quad Cab w/Cummins Turbo Diesel, 2009 Rockwood 2607, and 3 'yaks!
300W of Suntech Solar, a Rogue MPT-3024 Controller, and a Xantrex PW2000 Inverter