Is there enough head clearance on the lower inside corner? You might just be moving the impact point. I would put a small cushion where your head might hit. Otherwise hinging the top part frame is probably pretty simple (as per Comodave)
I am 6'1", and our camper door is 6' tall, but the cushion starts over the 1" aluminum frame.
On our Chien Hwa, the previous owner made a nice toolbox underfoot at the helm. Not only does that prevent me from stepping up and out the 5' door, but I found out the hard way it makes me tall enough to head-butt the ceiling handrails.