I really agree with going with quality and going back in years to afford what you want. For the coach I have, there was no big change between the 2004 and 2005 models so I am not sure what you are referring to. I have a Freightliner chassis and I do not have any issue with the chassis. I would look at Newmar, Tiffin and Country Coach.
With a diesel, the mileage is not as important as how well the coach has been taken care of.
I have a front door and it works fine but I would also be fine with a middle door. There will probably be a lot more important criteria once you start looking. Really make sure the floor plan is something you can live with.
