This is a tricky question because although your motor home is old, people do love them and some are into restoring them, rather then buying something new that is not built as well.  Partly, the price would depend on the condition of the transmission, frame and undercarriage of the vehicle.  What you might want to do is look on craigslist.com in your area and see what the prices of comparable motor homes are selling for right now ,as the summer season approaches.  This is a great time to sell.  I have seen a few of these 27 foot motor homes selling for anywhere from $600 to $6,000 dollars.  You never know what someone else is going to see when they look at the motor home.  Only you can know its true condition.   If you have saved the repair bills and believe in a certain value, start there and see what happens.  Another site that people use to sell almost anything, for a free post, is Kijiji.com.  Try both of those sites and see what happens.  It costs you nothing, and it could be a way to sample the consumers, to see what they would pay for your motor home.