I have doubled the amount of RAM on the server, going from 1 to 2 GB. This should definitely help on the hangs. Also, I have added management again, by using a Real Weasel PCI card. If there is any trouble with the machine now, I should have a fair chance to fix it from home or whereever I am.
I took some pictures of the current server setup. On top you can see the backup server for DNS/MX, which also controls the 4-port USB serial adapter, for management.