A friend of mine ran a regular in doors cctv camera outside, just sheltered under the eaves of his house.... he said it held up for years, until it was turned off once, it never came on again...
He reckoned it was the small amount of heat generated by the camera electronics that kept it dry inside... turning it off was fatal as moisture got in, and stayed.
Only detriment of dipping it in resin that I can think of is the heat dissipation of the processor and regulator.. you're adding a layer of insulation to them; no air movement over their surfaces, may bake them...?
You can buy waterproof bulkhead connectors (usb, Ethernet, power etc..), fit these to the side of a larger IPxx box, and connect to the Pi inside the box.
Good luck with it though!
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