Can you drive to a suburb to a farm supply store. You can get water tanks of all sizes there, a cousin on mine who we camp with bought a 30 gallon tank and a 12v pump.
Similar for the gas cans, you can buy ones larger than 5 gallon in those stores, don't store too much gas in the house, the fumes start to become an issue, store some in a shed or something.
I'm bringing all my electronic gear together, lights, radios, NiMH battery chargers and powering them from automotive cords from a 12v battery. This 12v battery will be charged by solar or an old vehicle alternator. Buy a spare one that matches your current vehicle from ebay or a junk yard then you have a spare for your vehicle. I'm adapting a pulley to the bottom of my pressure washer so it can drive the alternator as a small generator, that way the pressure washer engine that site unused most of the time gets some more use.