[NTLUG:Discuss] Internet logging, caching, routing

[techvista]

I'm looking for some good advice on how to set up caching of internet 
access (at least web pages) and logging internet access URL/IP and 
_content_ (both ways). The only content I wish to log is when it has a 
word for a set of words I'm looking for or is to/from a URL/ipaddr 
that's in a list. In the crude diagram below, please observe the IPaddrs 
I have set for each piece. The box is a PC I wish to do the caching and 
logging. Current layout:

.               -----------------
.     DSL     |  cache + log    |  Tomato
.     Modem --|->nicR--*--nicG--|->Router--> PCs and network printers
. 192.168.1.1 |    .7  *    .3  |      .2    .4,.6,.8        .5,.9
.              -----------------
Modem = Verizon Gateway (has router and firewall features)
* = Mandriva2008.1 system, two NICs (R and G), 4GB, plenty HD space
Router = 4-wired plus wireless running tomato (www.polarcloud.com/tomato)

1) Recommended package for caching? Squid 3.x?

2) Required config settings for transparent proxy (using Red and Green NICs)

3) Recommended package for logging by content (by key word, URL, or IP).
. Log URL/IP for src+dest, actual content (perhaps ascii-only parts logged)

4) Required config settings for logging and filtering of #3

5) What settings on the Modem and Router (especially if you use Tomato 
firmware), and the caching/logger system that sits between them, do I 
need to set up in order for a PC attached to the DSL modem to see the 
other PCs and network printers at the opposite end?

I have already spent several hours searching the 'net and trying 
different setups but can't seem to get it right. Any useful input is 
welcome. The more detailed, the better.