a trencher would work great actually as long as it goes deep enuf. My mini hoe can dig 10 feet deep so I guess you could call it a "big mini". I am in Minnesota so we dig everything in at LEAST 6 feet usually try to get closer to 8 just to be extra safe. Cause you know dam well that if it breaks its gonna be in the dead of winter and it will probably be 40 below zero and miserable. You are correct about the poly line and pressure fittings, thats the good stuff. Make sure they are very clean and get the stiffeners that go inside the line. We use them all the time, it is very rare to use copper on anything now days, around here anyways. And when you backfill DO NOT just start flinging dirt, cover the hole line with 3-4 inchs of dirt with a shovel to make sure you dont backfill it with a rock sitting on the line or you will be digging it back up next week when the rock crushs the line. START HOGGIN!!!!!