In reading up on the furnaces, it looks like they need to be removed to be properly cleaned and inspected. They are working good but they are 16 years old might be time to look them over. Anyone ever removed them, how big of a deal is it.
Don't really need to remove an Atwood furnace to clean it. You can reach all of its guts from the outside except the duct work. The ducts are usually under the couch and can be accessed ( partially ) from there. Do a search here for furnaces and also be aware that parts for most of them are hard to find.
Gary B
Good discussion here on furnaces and poking around in them. Ken (@kenhat) replaced his - might have some words of wisdom...
Need Hydro Flame Furnace Burner (http://www.foreforums.com/index.php?topic=23119.msg179535#msg179535)