solar panels

You could but only if you make a rack so they will clear over the vents and skylights. You would not want a panel over the refrigerator vent or cab-over escape hatch. On the roof directly, I think about 300 watts would be the max.

Why do you wamt 500 watts of solar? Usual rule of thumb is 100 watts per battery.

You will know when you measure it.

Sure as long as you got the room for the size of the panels