How to do file sharing between OS X platforms without airport, airdrop, or router.

If you don't have a netwrok (wireless or wired), then you can use a Firewire cable and move files from one to the other

http://support.apple.com/kb/ht1661

Or you could set up a computer-to-computer network using WiFi

http://support.apple.com/kb/PH3771

Both of these work between different versions of OSX

All Macs for many years have included Airport WiFi. You should be able to create an Ad-Hoc network between any 2 Macs and transfer files via file sharing

The Airport icon on the menu bar -> Create Network on one Mac. On the other Mac, choose -> Join Other network.

Besides a Firewire cable, you should also be able to connect an ethernet cable between any 2 Macs and they should see each other.

There is always a USB thumb drive and sneaker-net (hand carry files between systems via the Thumb Drive).

You could get a WiFi router, and use it to create a local network where all the Macs in the home could see each other. That will work even if you do not have an internet connection.

You could get an ethernet switch and plug all the Macs into the switch via ethernet cables and they would all see each other.