First of all: take a breath, rest. You are safe.
3000 passed since the Great War, and now there's only ruins. But at least, the worst is gone.
Go back to beginning. This world have some evil creatures and powerful enemies, so don't forget to call your friends.
You can try to Create big and rotating machineries and factories to provide you low cost and renewable energy, but don't you stress out yourself.
In the ruins, there's some of ancient futuristic energy to be forged with Mekanism, you can use it as your will too.
With no humans in the earth, Botania has became a solution after cables and nuclear power destroyed the world.
Even in death you can stay calm because of the Grave Stone.
The journey can provide many types of stuff, try to carry them in some Sophiscated Backbacks.
Dragons has been ruling the world, they are tough and can adapt into Ice and Fire environments, can you do it too?
And many more...
Primary The Ruin's philosophy is to be lightweighted, or at least, with only useful stuff.

