Have always thought bin entry doors should be a foot or so higher off the floor than they are. maybe another 18".. have never had a bin that when the unload ran empty there was any more than 18" or so up on the door, just enough to require you to keep the lower panel closed and try to awkwardly contort you body up and over it to clean it away from there so you could open the lower panel up. Another 18" higher, with steps leading up to it on the outside, and a fold-down ladder immediately next to the door inside that you could unlatch and flip down into the grain to climb down in. In my mind this ladder would be long enough that it would be at a very slight angle when it sits on a clean floor, and you can flip it back up and latch while sweep is running. Sounds like a lot, but very minimal expense / materials when done up front.