I believe the fold up steps you are looking for are the MORryde Stepabove steps. They come in different lengths depending on the height of your trailer floor from the ground and some models have a handrail that mounts to the side. I believe the handrail can be ordered as an add on but they do not fit 1st and 2nd generation steps with open side rails.
MORryde StepaboveThey are now making a detachable model. There are 2 brackets that mount below the door sill on the outside of the trailer as long as you have 2" with structure behind that 2" for mounting screws. The steps have trigger latches at the top that hook on to the bracket.
Both types can be purchased with adjustable legs at the bottom for uneven ground.