first check Net::Telnet::Cisco. it probably can take a port number and will probably work through your current terminal server setup (i'm assuming the terminal server connects to the console ports on the routers...). you may be able to get direct telnet access to the routers themselves and bypass the terminal server alltogether.

Net::Telnet::Cisco will let you send 'terminal length 0' and then 'show module' and you get the output back in a nice regular Perl array.

for SNMP you need direct access to the routers. there's no way i can think of to tunnel SNMP over the terminal server.

usually the easiest way to dig info from SNMP is to do a 'snmpwalk' of the device starting at .1 (make sure to set your snmpwalk program to dump full OIDs, it makes it easier later). walk the device to a file, search the file for things that match the current config, then lookup the OIDs at the ever handy MibDepot.

you'll often find information that isn't defined by the vendor MIBs but comes from some random 3rd party MIB.

Net::Telnet::Cisco will get you started pretty quick...