Since Hurricane Katrina gutted my home - and took all the sheetrock
with it - I am upgrading ALL of the wiring (used to be "mostly"
ungrounded throughout). Consequently, I want to add a new sub-panel
inside the home to which all circuits will run. This will eliminate
the present setup of an ungrounded 4-circuit box and another grounded
(but very old) fuse panel. The home is small - only about 1,000 sq.
feet. To power that sub-panel, here's the way I've got it sketched
out:

Outside and adjacent to the meter, I will add a single 100A main
circuit breaker in a dedicated box. That breaker will then supply
power to the sub-panel (about 30 feet away) via a #4, four-wire romex
cable with two hots, a neutral, and a ground. I will bond the ground
and neutral at the main circuit breaker outside and separate them at
the sub. The sub contains 12 breakers and has no main breaker. To
ground the system, I will run #6 copper wire from the 100A breaker box
outside to an 8-foot grounding rod just below the box.

Currently, another panel is also connected to the meter and it provides
power to the A/C, a detached shop, and the two old panels listed above.
My plan is to leave it in place as is (minus the two 60A breakers for
the old panels) and wire the new 100A breaker box to the meter as well.

Can I wire both boxes to the load side of the meter, or is there a
better or another way?

Any input on my plan or the question would be appreciated.