Hiking with a hand-drawn cart of some type is a much better solution to evacuating with only a backpack. A three or four-wheeled wagon is preferable to a wheelbarrow (single-wheel) or a two-wheeled cart, but any cart will support more weight than you can in a backpack.
The size of the wheels is a key factor in choosing a cart or wagon. Smaller wheels mean that you are somewhat restricted to smooth surfaces like walkways and roads. Sandy or rocky surfaces will present huge obstacles. Larger wheels can handle bad surfaces far better.
Animal-Drawn Carts and Wagons
Everything from goat-drawn carts and dogsleds up to horse-drawn wagons and stagecoaches have been used to transport goods and people through the ages. If you have access to any of these options, you will be able to move more goods and people far faster that hiking would allow.
The major problem with these options is that now you have to water, feed and care for the animals in addition to the humans. You are also somewhat restricted to smooth paths and roadways with carts and wagons.
Horseback Evac
While we are on the subject of animals… Horseback riding is another option which provides a faster evacuation than hiking.
Horses offer you a more nimble alternative to wagons – a true “off-road” option. But unless you have an experienced pack horse (and a pack frame for that horse), you won’t be able to carry very much. You will be restricted to backpacks and bags you can hang off or tie to the saddle.