I recently utilized an RPi2 as a serial console connected to a few Cisco router (s) in a server room from my desktops (W7 and Ubuntu). Worked just fine.
The above noted I also utilize another microrouter (a bit smaller than the Gli-Net AR300M) as a combo firewall, serial console, wired or wireless connection and out of band management for my alarm/automation panel (Leviton Omni-Pro 2). (connect to it via LAN / Serial port - USB).
Just SSH to the AR300M and use minicom or install SerToNet or open a local serial console or use Putty from windows…
You could also build a little out of band management box using VPN and a USB cellular modem stick.
Have a small stack of Cisco routers here somewhere in the basement…will give it a try with the Gli-Net AR300M.