One problem with panels on the roof laying flat is that’s the wrong angle for maximum efficiency.
Ex: up in Michigan during the summer panels should be at a 24 degree angle and in the winter it is 72. Not to mention length of usable light each day is low doing the winter.
That being said, I run one good 200 watt panel, Victron mppt charge controller, and 2 lithium batteries. With that system I can keep my ARB fridge running, power my inside lights, and charge laptop/phones. Next year we’ll see how it does with my red neck AC.
I bought an adjustable panel support so I can angle them correctly. You might be able to do something like that on a roof.