routing

Hi,
In linux I just want a quick & dirty fix to get all my interfaces talking to each other. This will obviously be changed when I get A-S IP’s and a backbone.
I have

eth0 – 192.168.1.1
eth1 – 192.168.2.1
eth2 – 192.168.3.1

Do I just:

route add -net 192.168.0.0 netmask 255.255.0.0 dev eth0

or:
route add -net 192.168.1.0 netmask 255.255.255.0 dev eth0
route add -net 192.168.2.0 netmask 255.255.255.0 dev eth0
route add -net 192.168.3.0 netmask 255.255.255.0 dev eth0
route add default gw 192.168.1.1

or something else?

Thanks..