Depending on the load of the refrigerator/freezer the following list should be able to maintain a combined refrigerator/freezer (especially if you are using a high efficiency type).

1000 W Pure sine wave inverter

80 Amp/hr 12V SLA deep cycle battery x2

30A MPPT Charge regulator

100W Mono Crystaline Solar PV panel (2 might be needed depending on geographical latitude)

With cabling etc - total cost would be around $1000 - $1300.

The SLA batteries could also be charged from a small Generator if no sunshine was available and with 160 A/hrs @ 12V (960 Whrs @ 50% duty cycle) should give around 1 to 2 days use for a medium sized A or A+ rated conventional fridge freezer (i.e rated at around 200 KWhr/year)

The solar power backup solution is expensive, that is until you run out of fuel for the Gennie.