I have been in your situation. I would NOT trust just any low voltage installer; there are so many variables in mounting cameras. Be sure whom you are hiring has the experience necessary to mount and give advice on IP Cameras.
First determine if you are going to use
Blue Iris or a NVR for your cameras
The suggestion above to buy your own Cat 6 is an important suggestion. If I were to do it again, I would certainly run two CAT 6 wires to every point I even thought I might mount a camera. Don't forget your inside the house network wiring, especially if you will have multiple rooms where you will need connectivity. TV's now and probably more in the future need streaming capabilities and connectivity to the internet.
I would do much what you are already doing. Think things through from the wire to the routing of the wire, where the holes are drilled to mount the camera (drilling into stucco or wood, mounting under a soffit, or some other method. What techniques does the installer use to ensure water proofing (actually water resistance). Research and buy your own cameras unless the installer uses the brand you desire at a similar price. Take an active part in watching the installer and understanding what they are doing so you will have an idea what was done when you inevitability need to change things a year or two later.
Routing your cable to the termination point is important. Think through what equipment you think you need, then buy more than you need. You will always find the need for more cameras once you have lived with your system for awhile. Don't scrimp on POE router)(s) and surge protection (especially since you have lightning in your area).
In short, if I were doing it again, I would pay for quality labor and know enough to research the parts that I need to make sure that I had the proper equipment for the the system that I desired.
