Can you militarize your property?

Sure it's your property, but I wouldn't put traps up.

Sandbags and a watchtower: Depends on local zoning and building codes.

Traps: No.

Guard dogs: Some places have ordinances limiting how many dogs you can keep and even what breeds, but generally you are allowed to have at least a couple of dogs.

Sandbags: check with your zoning regulations about objects left out in the yard at all times.

Fences: yes.

Traps--NO.

Watchtower: maybe. Again, check with zoning regulations and you'll probably need a building permit.

Guard dogs: yes--as long as they are not vicious--if they bite someone, get out or cause undue barking or noise, mess or other problems, you'll get cited, jailed or otherwise prohibited.

Why on earth would you---nah--never mind. I don't want to know.

You can lay sandbags around but you can't put up a watchtower because that contravenes privacy rights of neighbours, and you can set up traps because they contravene safety laws. You could get guard dogs, as long as the number of them is small and in agreement with local government pet policy.

What about getting counseling for paranoid thoughts?

You could not set up harmful traps. You could set up signaling devices to alert you in case zombies crossed the line. Zoning laws would determine how high a tower you could build. You can sandbag as high as a fence allowed by zoning. You may want to discuss these plans with a therapist.

Ask your homeowners's association to see if it will allow these things