With 4000 miles I would be more concerned that the seals dried out in the eng, trans or Genset. How many hrs on the genset? Condensation also is a concern in the fluids also as well as the wiring in the genset. It maybe a real gem or have the above problems and I would expect more than 30% off MRP for an 8 year old MH. What are the asking fror the MH? I would check for leaks and look for evidence of rust ion the dipsticks. Start the genset and make sure it starts and runs without surging and it runs the AC and other appliances.