Hardening, auditing, host security and network security on Slackware systems

What I would like to accomplish is:

1. Learn how to audit for host based intrusions and audit for network based intrusions.
2. Get some advice on how to identify (and patch) vulnerable software on my Slackware systems. I would like to learn to report bugs to upstream developers and also learn to write my own patches. However, I do already understand how to update and patch my system using pre-existing sources.
3. Learn what software tools can aid me in completing both task 1 and 2. (vulnerability scanner, fuzzer, password audit, NIDS, HIDS, etc)
4. Finally, I would like to learn how to harden a Slackware system. As I understand it, SELinux is not very accessible in Slackware. So I am interested in hearing opinions about the GRSecurity linux kernel patch; the pros, the cons and the feasibility of using this patch with Slackware.

I realize my requests cover a very wide range of topics. I do have some basic to intermediate knowledge of various parts of information security. I would like to expand on my current knowledge. I understand that what I am asking to learn will take time and effort.

I am not looking for an all inclusive answer. I am looking for recommendations, tips, tricks, and documentation that the community finds useful. Hopefully this thread can be a resource to others in the future as well.

The posts that sparked my interest are here and here.