I have done automatic watering systems in the past for guerrilla grows, all gravity fed, ran by hoses to each plant with a drip line, but I have found the length of time required to haul all the equipment in, planning and setting it all up, disguise it, and routinely maintain it was not worth the time. Also, hoses, reservoirs, pumps, and anything man made, stands out, and could potentially attract attention, and its not hard for somebody to follow a hose in the middle of the forest. I simply water once a week, when I go to visit my guerrilla plots, the key is to find close water sources in the area before you plant, knowing easiest access to the water. I use a couple 5 gallon buckets filled with water with lids for no spillage. In previous years, I have gotten away without even watering plants, there are lots of excellent water absorbing soil amendments you can use, like peat moss. Mulch also helps drastically in keeping moisture in the soil, and stops any evaporation. There are also things called polymer crystals and they can absorb a lot of water. So, in my opinion, its personal preference on watering and automatic watering systems, generally monster plants require a lot more water as opposed to smaller plants, so in theory, water every day through drip line would give you a much larger yeild. But the time, money and patience required to set all that up, could be put towards more plants instead. How many plants do you intend on growing, if its just a few, setting up a drip line could be very plausible, as long as the system was well camouflaged and disguised. You are right about trails, The less you visit a plot the better, Its better not to take the same path more then once, the more you walk the same path, the more the trail becomes beat down. It might not seem like that big of a deal, but that is how A LOT of new growers lose plants, they go every day, take the same path, and have a straight path beat down in the grass leading right to the plants, so easy a 4 year old kid could follow. There are people that look for marijuana, so the more stealthy and hidden everything is, the less chance you have of your plants being robbed, also do not tell anybody, trust nobody, very easy for a new grower to get excited and want to tell or show people, leading to their plants going missing right after. Hope that helps, happy growing
very damn good idea, except wit as little rain as ill be getting in the summer, id be screwed. 
