HELP, How do I remove the HEATER CORE on my 2008 TIFFIN PHAETON

[GarBaker]

I have a 2008 Tiffin Phaeton QSH and I would love for someone to chime in on how to remove the dashboard or a way to access the HEATER CORE. I am a mechanic for cars and trucks. I'm just looking for any short-cuts or easy ways to access the HEATER CORE.

I can't see how the Large Upper Dash Panel comes off or if I even need to remove it.
I did remove the center console with the two drawers and that gave me pretty good access to view the heater core box. Pictures Attached.
Do I need to release the Freon and remove the AC Hoses and Remove the whole A/C - Heater Core Box? or am I on the right track just trying to just remove the heater core box lid? I removed the Glovebox Drawer and I see 5 screws going downward towards the Door Entry Handle Dash. I believe I need to remove these screws next but before I do (Because it looks challenging) do I need to remove these to get access to the heater core box top?

I believe I have a Denso system. After watching a video of a guy on YouTube working on his A/C Hi-Pressure Switch. I have the labels on the outside like he pointed out where Denso labels them and I could make out a "D" on the worn out label.

Any Help would be greatly appreciated. Gary