My 10 year old stays in there overnight, no issues. When they were little both my kids slept in there, again no prob. I've slept in there before as have buddies of mine on long trips, it's fine for an adult as well. The bigger issue if you don't have AC is that it is a little steamier in there than the V due to less airflow. Add foam rubber or some other cushion though, the original ones are stone. Marlin mid is double the size.