I am always amazed how some folk think they can use high power appliances from the humble leisure battery but then I have grown up with electrical calculations ( mind you I still make mistakes !) I have a 280A.hr Li-PO4 battery and a 3kW inverter to compliment the caravans leisure battery. My 1200W heat gun takes about 150A from the battery no problem ( big cables to inverter) and I will use 260W of solar to try and keep the battery from going flat over about a week off grid , with judicious use of the electrical items (No TV or microwave , but a 60W electric cool box).
Re fitting solars on the roof I suggest you measure the roof and the fittings on it and then find out the sizes of various solar panels and see if you can squeeze them on in between the skylights . I have done this using a CAD program called nanocad 5 and played about with various panels until I found the best fit. i managed to squeeze on 260W onto the roof , even on my little 2 berth caravan.
RogerL may be a bit off in his calculations ( but close enough) as microwave ovens are highly inductive loads and will appear to take more current than the power rating plate details , the voltage and current are slightly out of phase ( current lagging the voltage) so a simple A.C current meter and separate voltmeter will show a higher wattage the the actual wattage being taken>For an accurate measurement you need a true RMS power meter which takes into account the phase angle
