I have a out building that is not heated, but has power, that is a bit closer to the road. I could then run a CAT6 cable from there to the house, but I don't think it will be close enough still, may shave 50-100ft off the run, I would have to walk it out.
I would not run CAT over the 328ft limit, if you need to run it further I would suggest getting two media converters and using fiber.
Is there a reason is has to be burred? Are there no poles? How is your power burred that far without a voltage drop or is there a 10kv line buried and a ground transformer near the house? -- CompTIA Network+ Certified