THere is a 'dog house' on the inside of the coach that can be removed to access the engine. I don't know what it would all entail to have to actually pull the motor in one of these, but I also haven't heard anyone experiencing a catastrophic failure either.
Our dealership always used a garage for engine changes. They would jack up the front, remove the suspension, and drop the engine out the bottom. They said it was by far the easiest way.