With the sleeping platform in place, the interior height of the van is the same as before the pop top was installed, with the exception of about 2.5 feet at the rear of the van (this is the area you enter the bed from). When you want stand up space in the van, for hanging out or cooking or whatever, you can stack the bed at the front over the driver and passenger seats. The bed is in three sections, with the front one being permanently mounted and the middle and bottom sections being easily removable, so they can be stacked out of the way. As far as headroom inside of the poptop while sleeping, there is more than enough room to sit upright in bed.