Make sure your generator is rated for enough power production to meet the 'surge' when the compressor starts. The surge is much higher than what it uses when running, only lasts a couple of seconds but should be taken into consideration.A better plan would be a small generator.
You wouldn't have to run the generator all day, just an hour or so every few hours to have the fridge/freezer cool it's self down again, and as long as you didn't open the doors it would last another few hours before you had to do it again.
Keeping frozen water jugs in your freezer also keeps the compressor from cycling so frequently, thus saving you money operating your freezer. We have a 7 cubic foot chest freezer and a 14 cubic foot chest freezer in addition to our fridge/freezer. We've got frozen water in all of them.I like the Idea of leaving some jugs of ice in the freezer to help keep it cold.
I have frozen jugs in mine, but it's ice/water for when we go hiking or camping...
I guess they are doing double duty too!