If I were buying, I would find out what the most it would cost me to replace the furnace & thermostat & deduct it from the $2800 as my offer.
If I were selling it I would find out what is wrong & get an estimate on the cost, or repair it if is is just the thermostat. I would take the hit to make the sale. Spend a $100 to sell it easier.
By your last post you sound confident that you have it price right.
Dan Sees, Full Timing in the MH & Part timing in a S&B In Hampstead, NC
2013 Winnebago Journey 42e, 2014 Featherlite Car Hauler 3110 17.5', 2008 Mazda MX5,
2008 Toyota FJ Cruiser