Some of these threads might help you determine the best date to set up your decorations.
When Do You Start Decorating?
When will you put your props out?
Anyone started putting out their displays yet?
Decorating on Oct 1st
There's nothing wrong with the Martha Stewart style of decorating. The first question needs to be are you going to make props or buy props.
Outdoor Halloween Decorations
Outdoor Decorations
Tombstone Yard Halloween Decorations
These threads can give you a idea of what people are buying and where they get the items from:
2012 Halloween/Autumn item sightings
Post your 2012 Halloween Purchases (Store Bought Items)
2011 Halloween/Autumn item sightings
2010 Halloween/Autumn item sightings
2009 Halloween/Autumn item sightings