It depends how much boondocking, how long and what you want to be able to use.
I originally added two more 6V batteries in my '20 Magnitude SV34. That would handle boondocking overnight with running both refrigerators, charging phones and making a couple pots of coffee in the morning.
I also installed two 160W Renogy flexible solar panels (my coach was solar ready and only came with a controller but no panels when it was first introduced).
Last year I upgraded to 850Ah of LiFePO4 batteries and this spring I upgraded my inverter to a Xantrex Freedom XC Pro 3000 Inverter / Charger. I rewired the coach so I can run any circuit off the inverter... like one A/C unit or the microwave. I also added an additional 175W solar panel.
__________________
|