Renee,
very sorry for your dog losses. I know I would be devestated if I lost our dog.
We live on acreage (only an acre so easy to maintain), and have acreage homes around us and a large Macadamia farm on our back fence. We have neighbours who have seen Browns, and King Browns, and we have seen none(apart from some pythons and green tree snakes).
We have purposely taken some simple steps (which I read about prior to moving in) and I think have made a difference.
1. Have no creepers (plants) in any of our gardens. All bushes or trees (nothing for them to hide in)
2. Have all of our garden beds on mounds with lawn in between which I keep at lawn length (snakes hate being in the open)
3. I don't store anything on the ground...it is off the ground or in the shed
4. The sheds always have mouse/rat baits in them, and I used expanding foam to fill in the gaps at the base of the shed walls to make it harder for any (rats/snakes) to crawl into the sheds.
5. We are lucky to have 2 resident kookaburras (they are territorial)
In the 5 years we have been in this house, we haven't seen any brown or black snakes whereas neighbours have.
Hope that helps.
MarkVS