Ayce has an article about his use of a poncho-tarp on a JMT thru hike http://thru-hiker.com/articles/ponchotarping.php
A lot of poncho-tarpers seem to use a bivy sack, which adds weight ... seeming to defeat the purpose of dual use shelter/raingear (partially). There are some pretty light bivies out there but the light ones I’ve actually seen don’t seem to have room for things like a larger hiker (me! ... but also some trim folks with northern European genetics) or a cold weather sleeping bag or a full length sleeping pad.
There’s also the problem of how you setup the shelter when you are in a cold rainstorm that just won’t quit. I think it is possible to do without getting soaked but it requires more than a little agility and it’s a skill you oughta work on before you hit the trail.
