k9, good for you, I don't know if the military reimburses you for training courses or not. If they do I would find a course near you to take, hands on labs are the best prep outside of actually working with cisco routers. Many community colleges offer CCNA courses. Do you have any other training, CompTIA, CNP, etc? You really need to understand the basics of networking, topologies, routing protocols, OSI model, etc. (not implying that you don't)
I find when interviewing people for networking positions most have certs out the ying yang but no real world experience, for some this is not a problem but others are challenged when asked to config a router for enterprise use.
If possible pick up a used cisco layer 3 switch like this one
http://cgi.ebay.com/Cisco-Catalyst-3500-Series-WS-C3524-XL-EN-Switch_W0QQitemZ320183382706QQihZ011QQcategoryZ280 40QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
This will give you some good hands on experience loading the IOS from scratch and becoming familiar with cisco command lines.
PM me some time I think I still have some CCNA training materials.
Good luck
Rob