Hi

Is it possible to set the the 2820 to reboot at a specific time?

I think it's done based on uptime, so you can set the router to reboot every 24 hours for instance - if you go to the router's telnet interface, enter:
sys autoreboot ?
to find out the syntax of it, it's usually just "sys autoreboot on" and "sys autoreboot 24" to make it restart every 24 hours from when it was started up.