Freezing tomatoes depends on electricity, or, if you have it, a gasoline or other fuel powered freezer.
Drying tomatoes requires dry heat. That's ok if they ripen early enough in the season for dry heat to be available. Otherwise one is dependent upon gas or electricity for drying.
Canning tomatoes requires a stove or fire.
One option we've heard of and are trying this year is wrapping tomatoes individually.
The technique suggested to us was that if tomatoes were individually wrapped and kept cool, that they would keep for a fairly long time. When needed, the tomatoes were to be taken out, ripened on the window sill, and used.
We'll see if this works. Our green tomatoes are individually wrapped and in a box in our garage. We'll set off part of the garage under the steps to keep it a bit warmer than the waaaay below freezing temps that we experience. Hopefully we can keep them above freezing and below 40 degrees.