I think I'll stick with your custom firmwares for now, there's no point in biting over too much at once.

So I need to do two things:
manually set the IP address of the three interfaces eth0, eth 0.1, and eth1. I assume this is done with the ifconfig command. it will most likely have to be run at every bootup (?), so in what files should I place the commands? Are the commands perhaps present in a file already so that I may edit them? I will also have to delete any bridges that are created and so forth.

Install additional routing software quagga. Is a USB flash drive sufficient? I do not really have the money to buy an external hard drive for each of the three routers. However, flash drives allow only a limited amount of write cycles, so they are not very suitable as storage for files that need frequent updating. What is the case with quagga? Also, will be installing the packet with ipkg ensure that the necessary daemons are started automatically at bootup?

Again, all your help is greatly appreciated!

Kolaf