I've been tasked with upgrading our network and could use some input. We have 2 networks coming in currently to a single C7206VXR. We are now adding a second 7206 and wish to use it properly to better balance our traffic and add some much-needed redundancy. We have a distribution layer consisting now of 5 Dell PowerConnect 5224s, which are replacing 100M C3500s.
Each 7206 has a PNE-G1 w/3 gigE ports, plus 2x PA-GE GigE and 2x 100M Ethernet cards.
[net1] [net2] | | <- NPE-G1 port  <->  | | <- PA-GE port [sw1 ] | [sw2 ] <----+ [sw3 ] [sw4 ]
Should I connect each incoming network to a separate 7206, then cross-connect the 2 7206s? If so, should I advertise the routes between the two dynamically or by using static routes?
At the distribution layer I am placing 2 switches in each of our 2 cabinets. How should I connect the 2 7206s? I initially though about designating a network to each switch, but should I instead just cascade all the switches and connect each 7206 to a different switch? OR, since I have 5 gigE ports on the routers, should I connect all the switches directly to the routers?
My goal is to use each of the components as efficiently as possible.