https://www.amazon.com/Woodland-Camouflage-Waterproof-Bivy-Cover/dp/B008JXV2PM
Definitely not for ultralight trips but I like the durability of it. I usually use a Costco down blanket and a static v pad so the whole system is pretty light. For going truly light weight when I’m worried about wind or whatever I use one of those sol(?) bivy bags or ground sheet, tarp, bag and pad and some times leave the tarp. If bugs are a problem I wear long clothing and a head net.
There's much better advice online about stealth camping than I could ever give here. However I can share my personal choices. It's very lightweight, and takes a very tired or very disciplined sleeper.
I have a US army bivy sack and whatever sleeping bag(s) you have inside. it's goretex which is totally waterproof on the outside, but it doesn't trap water vapor on the inside, so you and your sleeping bag stay dry:
(this one: http://www.amazon.com/Woodland-Camouflage-Waterproof-Bivy-Cover/dp/B008JXV2PM)
and a Thermarest air mattress. you need to stretch before bed and be dog tired to sleep on this thing but it's compact, fits in a bivy sack, and it traps your body heat before it seeps into the cold ground:
and it's a good idea to put a dark tarp down to keep poky sticks off your sack
You can scout a spot during the day, then wait and arrive when it's dark, camp in the dark, wake up and leave before light. I keep pepper spray in hand ($5 on amazon), mostly in case of animals, it's so cheap I just spray a little perimeter in the dirt around my head like I'm warding off witches. No human will be aware you exist and 99.9% of humans outside of Sketchville are okay people. Your car will be the hardest thing to hide (stealth camping is most ideal for hitch-hikers and cyclists). Be creative, find blogs on the subject, I'd think a suburban Walmart would have some nature around it shrouded in darkness, and a car affords you the luxury to drive out to the country where there's few people.
Oh another thing, a bivy sack lets you put your ear right up to the dirt and bugs, if that's your thing.
Also a side note, if you show up with a van to a farm it's going to be put to work, even if you built a home in it, you'd be towing trailers, likely through at least some feces. bring boots you don't mind walking through poop in too.
If you're flying solo then this army camo bivy is probably the best bang for your buck: http://www.amazon.com/Woodland-Camouflage-Waterproof-Bivy-Cover/dp/B008JXV2PM/ref=sr_1_1?ie=UTF8&qid=1450560885&sr=8-1&keywords=bivy+sack.
What Homelesswarrior said- a mummy bag. You want something that's insulated properly so that it rolls up tightly into a lower profile roll, rather than a camping bag that looks like you're carrying around a roll of fiberglass insulation under your arm. He also mentioned a small tent, and I will also recommend a bivy sack. Here is a good example of a waterproof bivy that your sleeping bag goes inside, here is another. These are best for stealth. If you want slightly more room, you can go with a bivy similar to this one, or go with a 1-person tent like this one, or this Nemo Sabre SE. I also recommend you maybe look into getting a headlamp, which you may find invaluable someday, especially if you like to read books the old fashioned way.
It would be great if you found a spot that is out of the way enough where you feel comfortable leaving your gear and don't have to break down your site every morning. Even if you can find an area where you can dig a hole deep enough to put a sterlite bin in, you can store your gear in the hole, and create a camouflage cover for the hole that just looks like the forest floor, or desert floor, or whatever environment you will be setting up camp.
Best of luck to you. Stay safe.