[rheavn]

"Can someone tell me how to access the top of the engine to adjust the valves?"

Chester,
I do not know exactly how yours comes apart. But I would look for similarities with how mine came apart. Start in the engine bay & look for the center section that comes apart. There must be a floor panel that is similar to mine, just not granite covered, that is in a closet or somewhere at the rear of the coach. Let us know what you find.