Outdoor WiFi extender

Based on what I have here in my setup, you would need an antenna to send a signal for each camera, because they are in different locations.  That could be done in two ways.  An antenna to send a signal to the other antenna in the barn as a relay then it goes from that antenna to the house or both antennas just sending the signal to the house receiving antenna.  That is assuming there are no obstructions in the way that could interfere with the signal, such as trees.  If that is the case, it is possible you may need another relay in the middle, but I don't think so as there are really powerful antenna bridges out now that should handle the distance.  

Protecting the wiring is important in these outdoor setups as well. So, I suggest getting those outlet boxes to mount the cameras on to protect the wiring that you are connecting the power and network through.  Silicone around those as well to protect water from penetrating.  I made that mistake one time and didn't properly silicone and it ended up frying the camera as moisture penetrated through to the connection.

Some others here may have a better way or idea to do this as there a lot of gurus here in the forum that know this stuff better than me, but hopefully this is helpful for you.