If you live somewhere where trees are common, consider a backpacking hammock. They set up in a minute or two (I once timed my hammock setup, without tarp, at 1 minute and 18 seconds), pack up quickly and you don’t need to find a flat place to hang your hammock. Rocky ground? Fine. Sloping ground? Fine. All you need are two trees far enough apart. They are also lightweight and their pack size is smaller than a loaf of bread.
The best of the camping hammocks in my experience are made by Warbonnet Outdoors Lightweight Camping Hammocks | Backpacking Hammocks | Warbonnet Outdoors . Their Blackbird and nearly identical, but larger XLS are incredibly comfortable. The Warbonnet hammocks are designed to allow you to sleep relatively flat, whereas many hammocks make you sleep in a “banana” shape, which can be tough on the knees. They have an integrated bug net. On the Blackbird it can be flipped out of the way and on the XLS it can be completely removed. If the weather is good, the hammock is all you need. If rain is in the forecast then you can pitch the hammock under a tarp.
This was my setup camping in a public campground in the Berkshires last weekend. I weathered a pretty strong thunderstorm during the night and stayed dry. This is a Warbonnet XLS with a tarp also made by Warbonnet.
This was our setup camping in the Adirondack wilderness several years ago. Two Warbonnet Blackbirds. Note the tarps are a bit lower than in the upper photo. Severe storms were predicted and lowering the tarp provides added protection. You can also pitch the tarp “front porch style” with poles holding up one end, to provide views even while laying in the hammock.
If the hammock is not an option for you, perhaps you can consider a bivy shelter or bivy sack. A bivy shelter is a solo tent that is very low to the ground. They set up quickly because they usually only have one or two poles. They basically are for sleeping only, as you can’t stand or even sit up in them. They pack small and are very lightweight, usually under 2 lbs. A good one is the Marmot Starlight Marmot Starlight 1 Person Tent and for a decent that is cheaper there is the Eureka! Solitaire Eureka Solitaire Tent .
A bivy sack is essentially a breathable, waterproof bag that slips over your sleeping bag. Bivy sacks are generally used by mountaineers, but are popular among those who want a light weight, no fuss campsite. Many have a single pole that keeps the bag out of your face and gives you breathing room. The downside is bivy sacks can be a bit warm to sleep in on hot summer nights. The Outdoor Research Helium Bivy is a good example of a bivy sack.
If the hammock and bivy ideas are a bit confining for you and you want a solo tent that you can at least sit up in the Flashlight 2 FL by Sierra Designs is a good choice. A more roomy, but expensive option is the Big Agnes Seedhouse Big Agnes Seedhouse SL 1 Tent . It is no longer in Big Agnes’ line, but can be found many places online.