Looking for ideas on rear ramp door

[82Motorsports]

I have an enclosed trailer that currently has swing doors on rear. I want to build a ramp door to replace it as my ramp idea doesn't work real well. The trailer sits higher than some so I'm looking to lower it first, but I'm looking for help on rear door. Anyone done this or tell me what to look out for in the build? What type of hinge(s) work best? Cable and pulley system, etc?

Thanks,
Dave