I particularly like the idea of the in use box outside and a regular keystone inside, that way it can just be disconnected in the off season. Some of the installations we did in celebration, fl had underground junction boxes set at ground level but the cost of these is a little outrageous. that said, if you need more than two runs of Ethernet cable to run your system the cost becomes moot as the waterproof in service box can cost 20+ easily. You could run conduit to a box outside in the ground and continue it to the permanent locations.
You might even use a weatherhead service entrance to keep water out of your box when you send your cables down to the junction. You could simply attach keystones in the junction box, run your show wires wherever else they need to go and run them down through the weatherhead entrance to the junction box, and connect them there.
The biggest key is to keep moisture away from the keystone jacks because they are not made to handle moisture. I installed some IP66 "weatherproof" cameras outside on a wall and not even 3 months later we had to cut off the pigtails and wire them up inside a weatherproof box.
YMMV.... Where I live you can get away with a lot when it is low voltage. Its the electric service that gets you in loads of trouble. Might be different/more stringent where you live. It is still true here that you cannot run service electricity in the same conduit with communications wire. Even when it is possible our inspectors frown upon it. Conduit is too cheap to combine them when you are messing with something that can burn your house down.
