Chances to generate bitcoins shouldn't depend on network connectivity above a certain base level. If you can receive blocks in a timely manner (somewhat low latency and a decently low packet loss), generating should only depend upon CPU speed (and maybe some other internal specs like memory speed).

Forwarding ports helps the network since more people can connect to you, but I'm running on a university network so I can't forward any ports and it works fine for me.

-connect is a command line option. Right click on your shortcut for Bitcoin, go to properties, and add "-connect=192.168.0.100" (no quotes, and replace the IP with the right one for you) to the end of the path.

July 12th: Edited to fix my command line.