I need to be pointed in the right direction to buy a used A,C, or bus that will tow 7,500 lbs. I would prefer 30 ft. but know I will probably need to go longer. Also think I want at least a 300hp diesel for power up hills. Has anyone made a short ,stout, powerful rig? What chassis will I need to go to and what makes and models were made on that chassis? I can beef up the hitch if the rest pencils.